diff --git a/extra/10816.cpp b/extra/10816.cpp
new file mode 100644
index 0000000..5c9b396
--- /dev/null
+++ b/extra/10816.cpp
@@ -0,0 +1,52 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int N, M;
+map<int, int> m;
+vector<int> v;
+
+int main()
+{
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+    cout.tie(NULL);
+
+    cin >> N;
+    for (int i = 0; i < N; i++)
+    {
+        int num;
+        cin >> num;
+        if (m.find(num) != m.end())
+        {
+            m[num]++;
+        }
+        else
+        {
+            m.insert({num, 1});
+            v.push_back(num); // 중복없이 저장
+        }
+    }
+
+    sort(v.begin(), v.end());
+
+    cin >> M;
+    for (int i = 0; i < M; i++)
+    {
+        int num;
+        cin >> num;
+        if (binary_search(v.begin(), v.end(), num))
+        {
+            cout << m[num];
+        }
+        else
+        {
+            cout << 0;
+        }
+
+        if (i != M - 1)
+        {
+            cout << " ";
+        }
+    }
+}
\ No newline at end of file
diff --git a/extra/10870.cpp b/extra/10870.cpp
new file mode 100644
index 0000000..4285172
--- /dev/null
+++ b/extra/10870.cpp
@@ -0,0 +1,27 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int n;
+
+int F[21] = {
+    0,
+};
+
+void go()
+{
+    F[0] = 0;
+    F[1] = 1;
+    for (int i = 2; i <= n; i++)
+    {
+        F[i] = F[i - 1] + F[i - 2];
+    }
+}
+
+int main()
+{
+    cin >> n;
+    go();
+
+    cout << F[n];
+}
\ No newline at end of file
diff --git a/extra/1654.cpp b/extra/1654.cpp
new file mode 100644
index 0000000..510e4aa
--- /dev/null
+++ b/extra/1654.cpp
@@ -0,0 +1,60 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int K, N;
+vector<int> v;
+int max_len = 1;
+long long sum = 0;
+
+void b_search()
+{
+    long long low = 0;
+    long long high = sum / N;
+    // 다 합한 뒤 필요한 개수로 나눔  = 최대 길이
+    while (low <= high)
+    {
+        long long mid = (low + high) / 2;
+        if (mid == 0)
+        {
+            return;
+        }
+        // 각 랜선을 최대 길이로 나눈 몫의 합이 N과 같거나 클때 까지 연산
+        int cnt = 0;
+        for (int i = 0; i < K; i++)
+        {
+
+            cnt += v[i] / mid;
+        }
+
+        if (cnt >= N)
+        {
+            if (max_len < mid)
+                max_len = mid;
+            low = mid + 1;
+        }
+        else if (cnt < N)
+        {
+            high = mid - 1;
+        }
+    }
+}
+
+int main()
+{
+
+    cin >> K >> N;
+    for (int i = 0; i < K; i++)
+    {
+        int a;
+        cin >> a;
+        v.push_back(a);
+        sum += a;
+    }
+
+    b_search();
+
+    cout << max_len;
+
+    return 0;
+}
\ No newline at end of file
diff --git a/extra/17843.cpp b/extra/17843.cpp
new file mode 100644
index 0000000..368d0e5
--- /dev/null
+++ b/extra/17843.cpp
@@ -0,0 +1,38 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int main()
+{
+    int n;
+    cin >> n;
+    while (n--)
+    {
+        int h, m, s;
+        cin >> h >> m >> s;
+
+        // 시침: 1시간 30도 / 1분 0.5도 / 1초 0.008333
+        double a = 30 * h + m * (0.5) + s * 0.008333333;
+
+        // 분침: 1분 6도 / 1초 0.1도
+        double b = m * 6 + s * 0.1;
+
+        // 초침: 1초 6도
+        double c = 6 * s;
+
+        double temp1 = abs(a - b);
+        double temp2 = abs(a - c);
+        double temp3 = abs(b - c);
+
+        if (temp1 > 180)
+            temp1 = 360 - temp1;
+        if (temp2 > 180)
+            temp2 = 360 - temp2;
+        if (temp3 > 180)
+            temp3 = 360 - temp3;
+
+        double answer = min({temp1, temp2, temp3});
+
+        cout << fixed << setprecision(6) << answer << '\n';
+    }
+}
\ No newline at end of file
diff --git a/extra/181832.cpp b/extra/181832.cpp
new file mode 100644
index 0000000..e82a69b
--- /dev/null
+++ b/extra/181832.cpp
@@ -0,0 +1,55 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+int a[30][30] = {
+    0,
+};
+
+vector<vector<int>> solution(int n)
+{
+    int curr = 1;
+    for (int i = 0; i < n; i++)
+    {
+        for (int j = 0; j < n; j++)
+        {
+            if (!a[i][j])
+            {
+                a[i][j] = curr;
+                curr++;
+            }
+        }
+        for (int j = 0; j < n; j++)
+        {
+            if (!a[j][n - i - 1])
+            {
+                a[j][n - i - 1] = curr;
+                curr++;
+            }
+        }
+        for (int j = 0; j < n; j++)
+        {
+            if (!a[n - i - 1][n - 1 - j])
+            {
+                a[n - i - 1][n - 1 - j] = curr;
+                curr++;
+            }
+        }
+        for (int j = 0; j < n; j++)
+        {
+            if (!a[n - 1 - j][i])
+            {
+                a[n - 1 - j][i] = curr;
+                curr++;
+            }
+        }
+    }
+    vector<vector<int>> answer(n, vector<int>(n, 0));
+    for (int i = 0; i < n; i++)
+    {
+        for (int j = 0; j < n; j++)
+        {
+            answer[i][j] = a[i][j];
+        }
+    }
+    return answer;
+}
\ No newline at end of file
diff --git a/extra/1845.cpp b/extra/1845.cpp
new file mode 100644
index 0000000..10bab42
--- /dev/null
+++ b/extra/1845.cpp
@@ -0,0 +1,27 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+map<int, int> m;
+
+int solution(vector<int> nums)
+{
+    for (int num : nums)
+    {
+        if (m.find(num) != m.end())
+        {
+            m[num]++;
+        }
+        else
+        {
+            m.insert({num, 1});
+        }
+    }
+
+    // 가져갈 포켓몬 수
+    int total = nums.size() / 2;
+
+    int answer = m.size();
+    if (answer > total)
+        return total;
+    return answer;
+}
\ No newline at end of file
diff --git a/extra/1920.cpp b/extra/1920.cpp
new file mode 100644
index 0000000..835a11d
--- /dev/null
+++ b/extra/1920.cpp
@@ -0,0 +1,52 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int N, M;
+vector<int> a;
+
+int b_search(int target, int low, int high)
+{
+    while (low <= high)
+    {
+        int mid = (low + high) / 2;
+        if (a[mid] == target)
+            return 1;
+
+        if (a[mid] > target)
+        {
+            high = mid - 1;
+        }
+        else if (a[mid] < target)
+        {
+            low = mid + 1;
+        }
+    }
+
+    return 0;
+}
+
+int main()
+{
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+    cout.tie(NULL);
+    cin >> N;
+    for (int i = 0; i < N; i++)
+    {
+        int num;
+        cin >> num;
+        a.push_back(num);
+    }
+
+    sort(a.begin(), a.end());
+
+    cin >> M;
+    for (int i = 0; i < M; i++)
+    {
+        int num;
+        cin >> num;
+        cout << b_search(num, 0, a.size() - 1) << '\n';
+    }
+    return 0;
+}
\ No newline at end of file
diff --git a/extra/2578.cpp b/extra/2578.cpp
new file mode 100644
index 0000000..1667383
--- /dev/null
+++ b/extra/2578.cpp
@@ -0,0 +1,94 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int a[5][5] = {
+    0,
+};
+
+vector<pair<int, int>> v(26, {0, 0});
+
+int cnt = 0;
+int answer = 0;
+
+bool check(int y, int x)
+{
+    // 당장 바뀐 부분만 체크
+    bool w = true;
+    bool h = true;
+    bool c1 = true;
+    bool c2 = true;
+
+    // 가로, 세로, 대각선
+    for (int i = 0; i < 5; i++)
+    {
+        if (a[y][i] != 1)
+            w = false;
+
+        if (a[i][x] != 1)
+            h = false;
+
+        if (y == x)
+        {
+            if (a[i][i] != 1)
+                c1 = false;
+        }
+        else
+        {
+            c1 = false;
+        }
+
+        if (y + x == 4)
+        {
+            if (a[4 - i][i] != 1)
+                c2 = false;
+        }
+        else
+        {
+            c2 = false;
+        }
+    }
+
+    if (w)
+        cnt++;
+    if (h)
+        cnt++;
+    if (c1)
+        cnt++;
+    if (c2)
+        cnt++;
+
+    if (cnt >= 3)
+        return true;
+
+    return false;
+}
+
+int main()
+{
+    for (int i = 0; i < 5; i++)
+    {
+        for (int j = 0; j < 5; j++)
+        {
+            int num;
+            cin >> num;
+            v[num] = {i, j};
+        }
+    }
+
+    for (int i = 0; i < 25; i++)
+    {
+        int num, y, x;
+        cin >> num;
+        tie(y, x) = v[num];
+        a[y][x] = 1;
+        if (check(y, x))
+        {
+            if (answer == 0)
+                answer = i + 1;
+        }
+    }
+
+    cout << answer;
+    return 0;
+}
\ No newline at end of file
diff --git a/extra/2579.cpp b/extra/2579.cpp
new file mode 100644
index 0000000..70842b2
--- /dev/null
+++ b/extra/2579.cpp
@@ -0,0 +1,41 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int A[301] = {
+    0,
+};
+
+int DP[301] = {
+    0,
+};
+
+int answer = 0;
+int n;
+
+void go()
+{
+    DP[1] = A[1];
+    DP[2] = A[1] + A[2];
+    DP[3] = max(A[1] + A[3], A[2] + A[3]);
+    for (int i = 4; i <= n; i++)
+    {
+        DP[i] = max(DP[i - 2] + A[i], DP[i - 3] + A[i - 1] + A[i]);
+    }
+}
+
+int main()
+{
+    cin >> n;
+
+    for (int i = 1; i <= n; i++)
+    {
+        int a;
+        cin >> a;
+        A[i] = a;
+    }
+
+    go();
+
+    cout << DP[n];
+}
\ No newline at end of file
diff --git a/extra/2805.cpp b/extra/2805.cpp
new file mode 100644
index 0000000..4a20bb4
--- /dev/null
+++ b/extra/2805.cpp
@@ -0,0 +1,46 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int N, M;
+vector<int> v;
+
+int main()
+{
+    cin >> N >> M;
+    for (int i = 0; i < N; i++)
+    {
+        int num;
+        cin >> num;
+        v.push_back(num);
+    }
+
+    sort(v.begin(), v.end());
+
+    int start = 0;
+    int end = v[N - 1]; // 가장 큰 나무
+    int max = -1;
+
+    while (start <= end)
+    {
+        long long sum = 0;
+        int mid = (start + end) / 2;
+
+        for (int i = 0; i < N; i++)
+        {
+            if (v[i] - mid > 0)
+                sum += v[i] - mid; // 자른 나무 길이
+        }
+
+        if (sum >= M)
+        {
+            start = mid + 1;
+            if (mid > max)
+                max = mid;
+        }
+        else
+            end = mid - 1;
+    }
+
+    cout << max;
+}
\ No newline at end of file
diff --git a/extra/42578.cpp b/extra/42578.cpp
new file mode 100644
index 0000000..e28c878
--- /dev/null
+++ b/extra/42578.cpp
@@ -0,0 +1,28 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+map<string, int> m;
+
+int solution(vector<vector<string>> clothes)
+{
+    int a = clothes.size();
+    for (int i = 0; i < a; i++)
+    {
+        if (m.find(clothes[i][1]) != m.end())
+        {
+            m[clothes[i][1]]++;
+        }
+        else
+        {
+            m.insert({clothes[i][1], 1});
+        }
+    }
+    int answer = 1;
+    for (auto it = m.begin(); it != m.end(); it++)
+    {
+        answer *= (it->second + 1);
+    }
+
+    return answer - 1;
+}
\ No newline at end of file
diff --git a/extra/42859.cpp b/extra/42859.cpp
new file mode 100644
index 0000000..6ee2831
--- /dev/null
+++ b/extra/42859.cpp
@@ -0,0 +1,81 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+const int MAX = 10000000;
+int a[MAX] = {0};
+vector<int> arr[9];
+
+int getException(int i, int n)
+{
+    int val = n;
+    for (int j = 0; j < i - 1; j++)
+    {
+        val = val * 10 + n;
+    }
+    return val;
+}
+
+int solution(int N, int number)
+{
+    arr[1].push_back(N);
+    a[N] = 1;
+
+    for (int i = 2; i < 9; i++)
+    {
+        int exceptionVal = getException(i, N);
+        if (exceptionVal < MAX)
+        { // getException 값이 MAX 이하인지 확인
+            arr[i].push_back(exceptionVal);
+            a[exceptionVal] = i; // 배열에 접근하기 전 확인
+        }
+        long long temp1, temp2, temp3, temp4;
+        for (int j = 1; j < i; j++)
+        {
+            for (int k = 0; k < arr[j].size(); k++)
+            {
+                for (int l = 0; l < arr[i - j].size(); l++)
+                {
+                    // 곱셈 연산
+                    temp1 = arr[j][k] * arr[i - j][l];
+                    if (temp1 > 0 && temp1 < MAX && a[temp1] == 0)
+                    {
+                        arr[i].push_back(temp1);
+                        a[temp1] = i;
+                    }
+
+                    // 나눗셈 연산 (0으로 나누기 방지)
+                    if (arr[i - j][l] != 0)
+                    {
+                        temp2 = arr[j][k] / arr[i - j][l];
+                        if (temp2 > 0 && temp2 < MAX && a[temp2] == 0)
+                        {
+                            arr[i].push_back(temp2);
+                            a[temp2] = i;
+                        }
+                    }
+
+                    // 더하기 연산
+                    temp3 = arr[j][k] + arr[i - j][l];
+                    if (temp3 > 0 && temp3 < MAX && a[temp3] == 0)
+                    {
+                        arr[i].push_back(temp3);
+                        a[temp3] = i;
+                    }
+
+                    // 빼기 연산
+                    temp4 = arr[j][k] - arr[i - j][l];
+                    if (temp4 > 0 && temp4 < MAX && a[temp4] == 0)
+                    {
+                        arr[i].push_back(temp4);
+                        a[temp4] = i;
+                    }
+                }
+            }
+        }
+    }
+
+    int answer = a[number];
+    if (answer == 0)
+        return -1;
+    return answer;
+}
diff --git a/extra/43105-1.cpp b/extra/43105-1.cpp
new file mode 100644
index 0000000..935755d
--- /dev/null
+++ b/extra/43105-1.cpp
@@ -0,0 +1,34 @@
+#include <string>
+#include <vector>
+#include <algorithm>
+
+using namespace std;
+
+int n = 0;
+
+int solution(vector<vector<int>> triangle)
+{
+    n = triangle.size();
+    vector<vector<int>> dp = triangle;
+    dp[0][0] = triangle[0][0];
+    dp[1][0] = triangle[0][0] + triangle[1][0];
+    dp[1][1] = triangle[0][0] + triangle[1][1];
+
+    for (int i = 2; i < n; i++)
+    {
+        dp[i][0] = dp[i - 1][0] + triangle[i][0];
+        for (int j = 1; j < i; j++)
+        {
+            dp[i][j] = max(dp[i - 1][j - 1] + triangle[i][j], dp[i - 1][j] + triangle[i][j]);
+        }
+        dp[i][i] = dp[i - 1][i - 1] + triangle[i][i];
+    }
+
+    int answer = dp[n - 1][0];
+    for (int i = 1; i < n; i++)
+    {
+        answer = max(answer, dp[n - 1][i]);
+    }
+
+    return answer;
+}
\ No newline at end of file
diff --git a/extra/43105.-2.cpp b/extra/43105.-2.cpp
new file mode 100644
index 0000000..5af7b3e
--- /dev/null
+++ b/extra/43105.-2.cpp
@@ -0,0 +1,16 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int solution(vector<vector<int>> triangle)
+{
+    int h = triangle.size();
+    for (int i = h - 2; i >= 0; i--)
+    {
+        for (int j = 0; j <= i; j++)
+        {
+            triangle[i][j] = max(triangle[i][j] + triangle[i + 1][j], triangle[i][j] + triangle[i + 1][j + 1]);
+        }
+    }
+    return triangle[0][0];
+}
\ No newline at end of file
diff --git a/extra/43162.cpp b/extra/43162.cpp
new file mode 100644
index 0000000..f30c325
--- /dev/null
+++ b/extra/43162.cpp
@@ -0,0 +1,32 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+vector<int> visited(200, 0);
+vector<vector<int>> computer;
+int N;
+
+void dfs(int here)
+{
+    visited[here] = 1;
+    for (int i = 0; i < N; i++)
+    {
+        if (visited[i] == 0 && computer[here][i])
+            dfs(i);
+    }
+}
+
+int solution(int n, vector<vector<int>> computers)
+{
+    computer = computers;
+    N = n;
+    int answer = 0;
+    for (int i = 0; i < n; i++)
+    {
+        if (visited[i] == 0)
+        {
+            dfs(i);
+            answer++;
+        }
+    }
+    return answer;
+}
\ No newline at end of file
diff --git a/extra/43163.cpp b/extra/43163.cpp
new file mode 100644
index 0000000..a8b4fd3
--- /dev/null
+++ b/extra/43163.cpp
@@ -0,0 +1,40 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+queue<string> q;
+map<string, int> visited;
+
+int solution(string begin, string target, vector<string> words)
+{
+    for (string i : words)
+    {
+        visited.insert({i, 0});
+    }
+    int wordlen = begin.length();
+
+    q.push(begin);
+    while (!q.empty())
+    {
+        begin = q.front();
+        q.pop();
+
+        if (begin == target)
+            break;
+        for (int i = 0; i < words.size(); i++)
+        {
+            int cnt = 0;
+            for (int j = 0; j < wordlen; j++)
+            {
+                if (begin[j] != words[i][j])
+                    cnt++;
+            }
+            if (cnt == 1 && !visited[words[i]])
+            {
+                q.push(words[i]);
+                visited[words[i]] = visited[begin] + 1;
+            }
+        }
+    }
+    return visited[target];
+}
\ No newline at end of file
diff --git a/extra/49189.cpp b/extra/49189.cpp
new file mode 100644
index 0000000..b7211f6
--- /dev/null
+++ b/extra/49189.cpp
@@ -0,0 +1,50 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+vector<int> adj[20001];
+vector<int> visited(20001, 0);
+queue<int> q;
+
+int solution(int n, vector<vector<int>> edge)
+{
+    for (int i = 0; i < edge.size(); i++)
+    {
+        adj[edge[i][0]].push_back(edge[i][1]);
+        adj[edge[i][1]].push_back(edge[i][0]);
+    }
+
+    q.push(1);
+    visited[1] = 1;
+    while (!q.empty())
+    {
+        int here = q.front();
+        q.pop();
+        for (int there : adj[here])
+        {
+            if (!visited[there])
+            {
+                q.push(there);
+                visited[there] = visited[here] + 1;
+            }
+        }
+    }
+
+    sort(visited.begin(), visited.end(), greater<>());
+    int max = visited[0];
+    int answer = 0;
+
+    for (int i : visited)
+    {
+        if (i == max)
+        {
+            answer++;
+        }
+        else
+        {
+            return answer;
+        }
+    }
+
+    return answer;
+}
\ No newline at end of file
diff --git a/week1/10808.cpp b/week1/10808.cpp
new file mode 100644
index 0000000..dcedf1f
--- /dev/null
+++ b/week1/10808.cpp
@@ -0,0 +1,23 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+vector<int> alphabet(26, 0);
+
+int main()
+{
+    string str;
+    cin >> str;
+
+    for (char i : str)
+    {
+        int idx = i - 'a';
+        alphabet[idx] = alphabet[idx] + 1;
+    }
+
+    // 출력
+    for (int i : alphabet)
+    {
+        cout << i << " ";
+    }
+}
\ No newline at end of file
diff --git a/week1/10988.cpp b/week1/10988.cpp
new file mode 100644
index 0000000..3983f17
--- /dev/null
+++ b/week1/10988.cpp
@@ -0,0 +1,20 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+int main()
+{
+    string str;
+    cin >> str;
+
+    for (int i = 0; i < str.length(); i++)
+    {
+        if (str[i] != str[str.length() - 1 - i])
+        {
+            cout << 0;
+            return 0;
+        }
+    }
+
+    cout << 1;
+    return 0;
+}
\ No newline at end of file
diff --git a/week1/1159.cpp b/week1/1159.cpp
new file mode 100644
index 0000000..7da4fc7
--- /dev/null
+++ b/week1/1159.cpp
@@ -0,0 +1,35 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+vector<int> v(26, 0);
+int main()
+{
+    int n;
+    cin >> n;
+
+    for (int i = 0; i < n; i++)
+    {
+        string name;
+        cin >> name;
+        int idx = name[0] - 'a';
+        v[idx] = v[idx] + 1;
+    }
+
+    // 출력
+    bool isPredaja = true;
+
+    for (int i = 0; i < v.size(); i++)
+    {
+        if (v[i] >= 5)
+        {
+            isPredaja = false;
+            cout << char('a' + i);
+        }
+    }
+
+    if (isPredaja == true)
+    {
+        cout << "PREDAJA";
+    }
+}
\ No newline at end of file
diff --git a/week1/11655.cpp b/week1/11655.cpp
new file mode 100644
index 0000000..8e04ae1
--- /dev/null
+++ b/week1/11655.cpp
@@ -0,0 +1,28 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int main()
+{
+    string s;
+    getline(cin, s);
+
+    for (int i : s)
+    {
+        if (i <= 'Z' && i >= 'A')
+        {
+            // 대문자
+            cout << char('A' + (i - 'A' + 13) % 26);
+        }
+        else if (
+            i <= 'z' && i >= 'a')
+        {
+            // 소문자
+            cout << char('a' + (i - 'a' + 13) % 26);
+        }
+        else
+        {
+            cout << char(i);
+        }
+    }
+}
\ No newline at end of file
diff --git a/week1/1213.cpp b/week1/1213.cpp
new file mode 100644
index 0000000..d78a55e
--- /dev/null
+++ b/week1/1213.cpp
@@ -0,0 +1,59 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+vector<int> v(26, 0);
+
+string getAnswer()
+{
+    string pre = "";
+
+    char center;
+    int centerCnt = 0;
+    for (int i = 0; i < 26; i++)
+    {
+        while (v[i] > 1)
+        {
+            v[i] = v[i] - 2;
+            pre.push_back('A' + i);
+        }
+        if (v[i] == 1)
+        {
+            center = 'A' + i;
+            centerCnt++;
+        }
+    }
+
+    string suf = pre;
+    reverse(suf.begin(), suf.end());
+
+    if (centerCnt > 1)
+    {
+        return "I'm Sorry Hansoo";
+    }
+    else if (centerCnt == 1)
+    {
+        return pre + center + suf;
+    }
+    else
+    {
+        return pre + suf;
+    }
+}
+
+int main()
+{
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+
+    string s;
+    cin >> s;
+
+    for (char i : s)
+    {
+        int idx = int(i - 'A');
+        v[idx] = v[idx] + 1;
+    }
+
+    cout << getAnswer();
+}
\ No newline at end of file
diff --git a/week1/1629.cpp b/week1/1629.cpp
new file mode 100644
index 0000000..f7e18fd
--- /dev/null
+++ b/week1/1629.cpp
@@ -0,0 +1,29 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+int main()
+{
+    int n;
+    while (cin >> n)
+    {
+        int a = 1;
+        int result = 1;
+
+        while (true)
+        {
+            if (a % n == 0)
+            {
+                cout << result << "\n";
+                break;
+            }
+            else
+            {
+                a = 10 * a + 1;
+                a %= n;
+                result++;
+            }
+        }
+    }
+
+    return 0;
+}
diff --git a/week1/1940.cpp b/week1/1940.cpp
new file mode 100644
index 0000000..3563c6e
--- /dev/null
+++ b/week1/1940.cpp
@@ -0,0 +1,39 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+vector<int> v(100001, 0);
+
+int main()
+{
+    int N, M;
+    cin >> N;
+    cin >> M;
+
+    for (int i = 0; i < N; i++)
+    {
+        int num;
+        cin >> num;
+        v[num] = 1;
+    }
+
+    int cnt = 0;
+    for (int i = 1; i < 100001; i++)
+    {
+        if (v[i] == 1)
+        {
+            int gap = M - i;
+            if (gap != i && gap > 0 && gap < 100001)
+            {
+                if (v[gap] == 1)
+                {
+                    cnt++;
+                    v[i] = 0;
+                    v[gap] = 0;
+                }
+            }
+        }
+    }
+
+    cout << cnt;
+}
\ No newline at end of file
diff --git a/week1/2309.cpp b/week1/2309.cpp
new file mode 100644
index 0000000..497599e
--- /dev/null
+++ b/week1/2309.cpp
@@ -0,0 +1,48 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+vector<int> height(9);
+int total = 0;
+
+pair<int, int> combi()
+{
+    int gap = total - 100;
+    for (int i = 0; i < 9; i++)
+    {
+        for (int j = i + 1; j < 9; j++)
+        {
+            if (height[i] + height[j] == gap)
+            {
+                return make_pair(height[i], height[j]);
+            }
+        }
+    }
+}
+
+void printAnswer()
+{
+    pair<int, int> fake = combi();
+
+    for (int i : height)
+    {
+
+        if (i != fake.first && i != fake.second)
+            cout << i << "\n";
+    }
+}
+
+int main()
+{
+    int num;
+    for (int i = 0; i < 9; i++)
+    {
+        cin >> num;
+        height[i] = num;
+        total += num;
+    }
+
+    sort(height.begin(), height.end());
+
+    printAnswer();
+}
\ No newline at end of file
diff --git a/week1/2559.cpp b/week1/2559.cpp
new file mode 100644
index 0000000..e2afa1a
--- /dev/null
+++ b/week1/2559.cpp
@@ -0,0 +1,41 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+map<int, string> m1;
+map<string, int> m;
+
+int main()
+{
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+
+    int N, M;
+    cin >> N >> M;
+
+    for (int i = 1; i <= N; i++)
+    {
+        string key;
+        cin >> key;
+
+        m1.insert({i, key});
+        m.insert({key, i});
+    }
+
+    for (int i = 0; i < M; i++)
+    {
+        string s;
+        cin >> s;
+
+        // 숫자이면 벡터에서 참조
+        if (int(s[0] - '0') < 10)
+        {
+            cout << m1[stoi(s)] << "\n";
+        }
+        else
+        {
+            // 문자열이면 맵에서 찾기
+            cout << m[s] << "\n";
+        }
+    }
+}
\ No newline at end of file
diff --git a/week1/2979.cpp b/week1/2979.cpp
new file mode 100644
index 0000000..b091b1d
--- /dev/null
+++ b/week1/2979.cpp
@@ -0,0 +1,50 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+vector<int> v(100, 0);
+
+void fillVec(int start, int end)
+{
+    for (int i = start; i < end; i++)
+    {
+        v[i] = v[i] + 1;
+    }
+}
+
+int getAnswer(int A, int B, int C)
+{
+    int sum = 0;
+    for (int i : v)
+    {
+        if (i == 1)
+        {
+            sum += A;
+        }
+        else if (i == 2)
+        {
+            sum += B * 2;
+        }
+        else if (i == 3)
+        {
+            sum += C * 3;
+        }
+    }
+
+    return sum;
+}
+
+int main()
+{
+    int A, B, C;
+    cin >> A >> B >> C;
+
+    for (int i = 0; i < 3; i++)
+    {
+        int start, end;
+        cin >> start >> end;
+        fillVec(start, end);
+    }
+
+    cout << getAnswer(A, B, C);
+}
\ No newline at end of file
diff --git a/week1/3986.cpp b/week1/3986.cpp
new file mode 100644
index 0000000..5c9f033
--- /dev/null
+++ b/week1/3986.cpp
@@ -0,0 +1,40 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int main()
+{
+    int cnt = 0;
+    int n;
+    cin >> n;
+    while (n--)
+    {
+        string s;
+        cin >> s;
+
+        // 짝수일때만 고려
+        if (s.length() % 2 == 0)
+        {
+            stack<char> st;
+            for (char i : s)
+            {
+
+                if (!st.empty() && st.top() == i)
+                {
+                    st.pop();
+                }
+                else
+                {
+                    st.push(i);
+                }
+            }
+
+            if (st.empty())
+            {
+                cnt++;
+            }
+        }
+    }
+
+    cout << cnt;
+}
\ No newline at end of file
diff --git a/week1/9375.cpp b/week1/9375.cpp
new file mode 100644
index 0000000..0960bb9
--- /dev/null
+++ b/week1/9375.cpp
@@ -0,0 +1,47 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int combiCnt(map<string, int> m)
+{
+    int mul = 1;
+
+    for (auto it : m)
+    {
+        mul *= (it.second + 1);
+    }
+
+    return mul - 1;
+}
+int main()
+{
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+
+    int T, N;
+    cin >> T;
+    while (T--)
+    {
+        map<string, int> m;
+        cin >> N;
+
+        while (N--)
+        {
+            string a, b;
+            cin >> a >> b;
+
+            if (m.find(b) != m.end())
+            {
+                int temp = m[b];
+                m.erase(b);
+                m.insert({b, temp + 1});
+            }
+            else
+            {
+                m.insert({b, 1});
+            }
+        }
+
+        cout << combiCnt(m) << "\n";
+    }
+}
\ No newline at end of file
diff --git a/week1/9996.cpp b/week1/9996.cpp
new file mode 100644
index 0000000..c85424c
--- /dev/null
+++ b/week1/9996.cpp
@@ -0,0 +1,45 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+int main()
+{
+    int n;
+    cin >> n;
+
+    string pattern;
+    cin >> pattern;
+
+    auto idx = pattern.find('*');
+
+    string prefix = pattern.substr(0, idx);
+    int prefixLen = prefix.length();
+    string suffix = pattern.substr(idx + 1);
+    int suffixLen = suffix.length();
+
+    for (int i = 0; i < n; i++)
+    {
+        bool isDa = false;
+        string str;
+        cin >> str;
+
+        if (str.length() >= prefixLen + suffixLen)
+        {
+            if (str.substr(0, prefixLen) == prefix)
+            {
+                if (str.substr(str.length() - suffixLen) == suffix)
+                {
+                    isDa = true;
+                }
+            }
+        }
+
+        if (isDa)
+        {
+            cout << "DA" << "\n";
+        }
+        else
+        {
+            cout << "NE" << "\n";
+        }
+    }
+}
\ No newline at end of file
diff --git a/week2/1012.cpp b/week2/1012.cpp
new file mode 100644
index 0000000..8688a33
--- /dev/null
+++ b/week2/1012.cpp
@@ -0,0 +1,68 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+int T, N, M, K;
+
+int a[50][50];
+int visited[50][50];
+
+vector<int> dy = {-1, 0, 0, 1};
+vector<int> dx = {0, 1, -1, 0};
+
+void dfs(int y, int x)
+{
+    visited[y][x] = 1;
+    for (int i = 0; i < 4; i++)
+    {
+        int ny = y + dy[i];
+        int nx = x + dx[i];
+
+        if (ny < 0 || nx < 0 || ny >= N || nx >= M)
+            continue;
+        if (a[ny][nx] == 0)
+            continue;
+        if (visited[ny][nx] == 1)
+            continue;
+
+        dfs(ny, nx);
+    }
+}
+
+int go()
+{
+    int cnt = 0;
+    for (int y = 0; y < N; y++)
+    {
+        for (int x = 0; x < M; x++)
+        {
+            if (a[y][x] == 1 && visited[y][x] == 0)
+            {
+                dfs(y, x);
+                cnt++;
+            }
+        }
+    }
+
+    return cnt;
+}
+int main()
+{
+    // 입력
+    cin >> T;
+    for (int i = 0; i < T; i++)
+    {
+        cin >> M >> N >> K;
+
+        for (int j = 0; j < K; j++)
+        {
+            int X, Y;
+            cin >> X >> Y;
+            a[Y][X] = 1;
+        }
+        cout << go() << "\n";
+        // 초기화
+        memset(a, 0, sizeof(a));
+        memset(visited, 0, sizeof(visited));
+    }
+    return 0;
+}
\ No newline at end of file
diff --git a/week2/1068.cpp b/week2/1068.cpp
new file mode 100644
index 0000000..f06accd
--- /dev/null
+++ b/week2/1068.cpp
@@ -0,0 +1,71 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+vector<int> child_list[50];
+int visited[50] = {
+    0,
+};
+int cnt = 0;
+
+int dfs(int here)
+{
+    if (visited[here] == 0)
+    {
+        visited[here] = 1;
+
+        for (int there : child_list[here])
+        {
+            if (!visited[there])
+                dfs(there);
+        }
+        if (child_list[here].size() == 0)
+        {
+            cnt++;
+        }
+        if (child_list[here].size() == 1 && visited[child_list[here][0]] == 2)
+        {
+            cnt++;
+        }
+    }
+    return cnt;
+}
+
+void removeChild(int remove)
+{
+    if (child_list[remove].size())
+        for (int child : child_list[remove])
+        {
+
+            removeChild(child);
+            child_list[child].clear();
+        }
+
+    return;
+}
+
+int main()
+{
+    int N;
+    cin >> N;
+    int root;
+    for (int i = 0; i < N; i++)
+    {
+        int p;
+        cin >> p;
+        if (p != -1)
+        {
+            child_list[p].push_back(i);
+        }
+        else
+        {
+            root = i;
+        }
+    }
+    int remove;
+    cin >> remove;
+    // 삭제한 노드는 이미 방문한 것으로 처리
+    visited[remove] = 2;
+
+    // 리프 노드 수 구하기
+    cout << dfs(root);
+}
\ No newline at end of file
diff --git a/week2/1325.cpp b/week2/1325.cpp
new file mode 100644
index 0000000..a579879
--- /dev/null
+++ b/week2/1325.cpp
@@ -0,0 +1,68 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+vector<int> adj[10001];
+int visited[10001] = {
+    0,
+};
+
+int cnt = 0;
+
+vector<int> result;
+
+void dfs(int here)
+{
+    visited[here] = 1;
+    cnt++;
+
+    for (int there : adj[here])
+    {
+        if (!visited[there])
+        {
+            dfs(there);
+        }
+    }
+}
+
+int main()
+{
+    int N, M;
+    cin >> N >> M;
+    for (int i = 0; i < M; i++)
+    {
+        int A, B;
+        cin >> A >> B;
+
+        adj[B].push_back(A);
+    }
+
+    int max = 0;
+    for (int j = 1; j <= N; j++)
+    {
+        dfs(j);
+        if (max < cnt)
+        {
+            result.clear();
+            result.push_back(j);
+            max = cnt;
+        }
+        else if (max == cnt)
+        {
+            result.push_back(j);
+        }
+        // 초기화
+        cnt = 0;
+        memset(visited, 0, sizeof(visited));
+    }
+
+    sort(result.begin(), result.end());
+
+    for (int i = 0; i < result.size() - 1; i++)
+    {
+        cout << result[i] << " ";
+    }
+    cout << result[result.size() - 1];
+
+    return 0;
+}
\ No newline at end of file
diff --git a/week2/1436.cpp b/week2/1436.cpp
new file mode 100644
index 0000000..5eec8f2
--- /dev/null
+++ b/week2/1436.cpp
@@ -0,0 +1,23 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int MAX = 10000666;
+vector<int> a;
+
+int main()
+{
+    for (int i = 666; i < MAX; i++)
+    {
+        string str = to_string(i);
+        if (str.find("666") != string::npos)
+        {
+            a.push_back(stoi(str));
+        }
+    }
+
+    int N;
+    cin >> N;
+    cout << a[N - 1];
+    return 0;
+}
\ No newline at end of file
diff --git a/week2/1992.cpp b/week2/1992.cpp
new file mode 100644
index 0000000..4f64971
--- /dev/null
+++ b/week2/1992.cpp
@@ -0,0 +1,59 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+string a[64];
+int N;
+vector<char> v;
+
+void go(pair<int, int> p, int size)
+{
+    int y, x;
+    tie(y, x) = p;
+    int key = a[y][x];
+
+    if (size == 1)
+    {
+        v.push_back(char(key));
+        return;
+    }
+
+    for (int i = 0; i < size; i++)
+    {
+        for (int j = 0; j < size; j++)
+        {
+            if (key != a[y + i][x + j])
+            {
+                v.push_back('(');
+                go({y, x}, size / 2);
+                go({y, x + size / 2}, size / 2);
+                go({y + size / 2, x}, size / 2);
+                go({y + size / 2, x + size / 2}, size / 2);
+                v.push_back(')');
+                return;
+            }
+        }
+    }
+
+    // 모두 같다면
+    v.push_back(char(key));
+    return;
+}
+
+int main()
+{
+    cin >> N;
+    for (int i = 0; i < N; i++)
+    {
+        string s;
+        cin >> s;
+        a[i] = s;
+    }
+
+    go({0, 0}, N);
+
+    for (char a : v)
+    {
+        cout << a;
+    }
+}
\ No newline at end of file
diff --git a/week2/2178.cpp b/week2/2178.cpp
new file mode 100644
index 0000000..6d78cf6
--- /dev/null
+++ b/week2/2178.cpp
@@ -0,0 +1,63 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int N, M;
+string a[101];
+int cnt = 0;
+int visited[101][101] = {
+    0,
+};
+int dy[] = {-1, 1, 0, 0};
+int dx[] = {0, 0, -1, 1};
+
+queue<pair<int, int>> q;
+
+void bfs()
+{
+    // 최단거리 탐색
+    //(1,1) ~(N,M)
+    int y = 1;
+    int x = 1;
+
+    q.push(make_pair(y, x));
+    visited[y][x] = 1;
+
+    while (q.size())
+    {
+        tie(y, x) = q.front();
+        q.pop();
+
+        for (int i = 0; i < 4; i++)
+        {
+            int ny = y + dy[i];
+            int nx = x + dx[i];
+
+            if (ny < 1 || nx < 1 || ny > N || nx > M)
+                continue;
+            if (visited[ny][nx] != 0)
+                continue;
+            if (a[ny][nx] == '0')
+                continue;
+
+            q.push(make_pair(ny, nx));
+            visited[ny][nx] = visited[y][x] + 1;
+        }
+    }
+}
+int main()
+{
+    cin >> N >> M;
+    for (int i = 0; i < N; i++)
+    {
+        string str;
+        cin >> str;
+        str = '0' + str;
+        a[i + 1] = str;
+    }
+
+    bfs();
+
+    cout << visited[N][M];
+    return 0;
+}
\ No newline at end of file
diff --git a/week2/2468.cpp b/week2/2468.cpp
new file mode 100644
index 0000000..0aade1b
--- /dev/null
+++ b/week2/2468.cpp
@@ -0,0 +1,86 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int N;
+int a[100][100] = {
+    0,
+};
+int visited[100][100] = {
+    0,
+};
+
+int dy[] = {-1, 1, 0, 0};
+int dx[] = {0, 0, 1, -1};
+
+int limit = 0;
+
+vector<int> result;
+
+void dfs(int y, int x)
+{
+    visited[y][x] = 1;
+
+    for (int i = 0; i < 4; i++)
+    {
+        int ny = y + dy[i];
+        int nx = x + dx[i];
+
+        if (ny < 0 || nx < 0 || ny >= N || nx >= N)
+            continue;
+        if (visited[ny][nx])
+            continue;
+        if (a[ny][nx] <= limit)
+            continue;
+
+        dfs(ny, nx);
+    }
+}
+
+void go()
+{
+    // 가능한 높이 = 0~100
+    for (int k = 0; k < 101; k++)
+    {
+        limit = k;
+        int cnt = 0;
+        memset(visited, 0, sizeof(visited));
+        for (int i = 0; i < N; i++)
+        {
+            for (int j = 0; j < N; j++)
+            {
+                if (a[i][j] > limit && visited[i][j] == 0)
+                {
+                    dfs(i, j);
+                    cnt++;
+                }
+            }
+        }
+        result.push_back(cnt);
+    }
+}
+
+int main()
+{
+    // 입력
+    cin >> N;
+
+    for (int i = 0; i < N; i++)
+    {
+        for (int j = 0; j < N; j++)
+        {
+            int height;
+            cin >> height;
+            a[i][j] = height;
+        }
+    }
+
+    // 높이 별 카운트 세기
+    go();
+
+    // 최댓값 찾기
+    sort(result.begin(), result.end(), greater<>());
+    cout << result[0];
+
+    return 0;
+}
\ No newline at end of file
diff --git a/week2/2583.cpp b/week2/2583.cpp
new file mode 100644
index 0000000..5db218e
--- /dev/null
+++ b/week2/2583.cpp
@@ -0,0 +1,92 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+int M, N, K;
+
+int a[100][100] = {
+    0,
+};
+
+int visited[100][100] = {
+    0,
+};
+
+int cnt = 0;
+int temp_width = 0;
+vector<int> width;
+
+const int dy[] = {-1, 1, 0, 0};
+const int dx[] = {0, 0, 1, -1};
+
+void dfs(int y, int x)
+{
+    temp_width++;
+    visited[y][x] = 1;
+    for (int i = 0; i < 4; i++)
+    {
+        int ny = y + dy[i];
+        int nx = x + dx[i];
+
+        if (ny < 0 || nx < 0 || ny >= M || nx >= N)
+            continue;
+        if (visited[ny][nx])
+            continue;
+        if (a[ny][nx])
+            continue;
+
+        dfs(ny, nx);
+    }
+}
+
+void go()
+{
+
+    for (int i = 0; i < M; i++)
+    {
+        for (int j = 0; j < N; j++)
+        {
+            if (a[i][j] == 0 && !visited[i][j])
+            {
+                dfs(i, j);
+                width.push_back(temp_width);
+                temp_width = 0;
+                cnt++;
+            }
+        }
+    }
+}
+
+void fill(int xl, int yl, int xr, int yr)
+{
+
+    for (int y = yl; y < yr; y++)
+    {
+        for (int x = xl; x < xr; x++)
+        {
+            a[y][x] = 1;
+        }
+    }
+}
+int main()
+{
+    cin >> M >> N >> K;
+
+    for (int i = 0; i < K; i++)
+    {
+        int xl, yl, xr, yr;
+        cin >> xl >> yl >> xr >> yr;
+        fill(xl, yl, xr, yr);
+    }
+
+    go();
+
+    sort(width.begin(), width.end());
+    cout << cnt << '\n';
+
+    for (int i : width)
+    {
+        cout << i << " ";
+    }
+
+    return 0;
+}
\ No newline at end of file
diff --git a/week2/2636.cpp b/week2/2636.cpp
new file mode 100644
index 0000000..c2e04d9
--- /dev/null
+++ b/week2/2636.cpp
@@ -0,0 +1,89 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int N, M;
+
+int a[100][100] = {
+    0,
+};
+
+int visited[100][100] = {
+    0,
+};
+
+const int dy[] = {-1, 1, 0, 0};
+const int dx[] = {0, 0, 1, -1};
+
+int remain = 0;
+int border = 0;
+int last_border = 0;
+int total_time = 0;
+
+void dfs(int y, int x)
+{
+    visited[y][x] = 1;
+    for (int i = 0; i < 4; i++)
+    {
+        int ny = y + dy[i];
+        int nx = x + dx[i];
+
+        if (ny < 0 || nx < 0 || ny >= N || nx >= M)
+            continue;
+        if (visited[ny][nx])
+            continue;
+
+        // 가장자리의 치즈라면 0으로 바꾸고 방문처리, 탐색은 이어서 X
+        if (a[ny][nx] == 1)
+        {
+            a[ny][nx] = 0;
+            visited[ny][nx] = 1;
+            border++;
+        }
+        else
+        {
+            // 빈 공간이라면 이어서 탐색
+            dfs(ny, nx);
+        }
+    }
+}
+
+void go()
+{
+    while (1)
+    {
+        if (remain == 0)
+            break;
+
+        dfs(0, 0);
+        remain -= border;
+        last_border = border;
+        border = 0;
+        total_time++;
+        memset(visited, 0, sizeof(visited));
+    }
+}
+
+int main()
+{
+    cin >> N >> M;
+    for (int i = 0; i < N; i++)
+    {
+        for (int j = 0; j < M; j++)
+        {
+            int num;
+            cin >> num;
+            a[i][j] = num;
+            if (num)
+            {
+                remain++;
+            }
+        }
+    }
+
+    go();
+
+    cout << total_time << '\n';
+    cout << last_border << '\n';
+    return 0;
+}
\ No newline at end of file
diff --git a/week2/2828.cpp b/week2/2828.cpp
new file mode 100644
index 0000000..1ec1e03
--- /dev/null
+++ b/week2/2828.cpp
@@ -0,0 +1,45 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+int N, M, J;
+
+int sum = 0;
+pair<int, int> bucket;
+
+pair<int, int> go(int loc)
+{
+
+    int temp = 0;
+
+    if (loc < bucket.first)
+    {
+        temp = bucket.first - loc;
+        sum += temp;
+        bucket.first = loc;
+        bucket.second = bucket.second - temp;
+    }
+    else if (loc > bucket.second)
+    {
+
+        temp = loc - bucket.second;
+        sum += temp;
+        bucket.first = bucket.first + temp;
+        bucket.second = loc;
+    }
+
+    return bucket;
+}
+int main()
+{
+    cin >> N >> M;
+    cin >> J;
+    bucket = {1, M};
+    for (int i = 0; i < J; i++)
+    {
+        int loc;
+        cin >> loc;
+        bucket = go(loc);
+    }
+
+    cout << sum;
+}
\ No newline at end of file
diff --git a/week2/2852.cpp b/week2/2852.cpp
new file mode 100644
index 0000000..48b5b1c
--- /dev/null
+++ b/week2/2852.cpp
@@ -0,0 +1,105 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int a = 0;
+int b = 0;
+
+int sum[3] = {
+    0,
+};
+
+int present = 0;
+string change_time = "00:00";
+
+pair<int, string> v[100];
+vector<int> state;
+
+int calculator(string a, string b)
+{
+    int asec = stoi(a.substr(0, 2)) * 60 + stoi(a.substr(3, 2));
+    int bsec = stoi(b.substr(0, 2)) * 60 + stoi(b.substr(3, 2));
+    return abs(asec - bsec);
+}
+
+string to_formatted_string(int num)
+{
+    if (num < 10)
+    {
+        return '0' + to_string(num);
+    }
+    else
+    {
+        return to_string(num);
+    }
+}
+
+string format(int sum)
+{
+    if (sum == 0)
+        return "00:00";
+    int min = sum / 60;
+    int sec = sum % 60;
+
+    return to_formatted_string(min) + ':' + to_formatted_string(sec);
+}
+
+int main()
+{
+    int n;
+    cin >> n;
+    for (int i = 0; i < n; i++)
+    {
+        pair<int, string> p;
+        cin >> p.first >> p.second;
+        v[i] = p;
+    }
+
+    for (pair<int, string> p : v)
+    {
+        if (p.first == 1)
+        {
+            a++;
+        }
+        else if (p.first == 2)
+        {
+            b++;
+        }
+
+        if (a > b)
+        {
+            state.push_back(1);
+        }
+        else if (b > a)
+        {
+            state.push_back(2);
+        }
+        else
+        {
+            state.push_back(0);
+        }
+    }
+
+    // state가 1->0 || 2->0으로 바뀔때 저장
+    // stack 1-> 1 / 2->2 일떈 누적
+    for (int i = 0; i < state.size(); i++)
+    {
+        if (present != state[i])
+        {
+            sum[present] += calculator(v[i].second, change_time);
+            change_time = v[i].second;
+            present = state[i];
+        }
+
+        // 마지막 요소
+        if (i == state.size() - 1)
+        {
+            sum[present] += calculator("48:00", change_time);
+        }
+    }
+
+    cout << format(sum[1]) << '\n';
+    cout << format(sum[2]);
+
+    return 0;
+}
\ No newline at end of file
diff --git a/week2/2870.cpp b/week2/2870.cpp
new file mode 100644
index 0000000..814b8a5
--- /dev/null
+++ b/week2/2870.cpp
@@ -0,0 +1,77 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+vector<string> v;
+
+void go(string str)
+{
+    string num = "";
+    for (char c : str)
+    {
+        if (c >= '0' && c <= '9')
+        {
+            // 숫자라면
+            num += c;
+        }
+        else
+        {
+            // 문자라면
+            if (num != "")
+            {
+                // 0제거
+                while (num != "0" && num[0] == '0')
+                {
+                    num.erase(0, 1);
+                }
+
+                v.push_back(num);
+            }
+            num = "";
+        }
+    }
+
+    // 마지막요소라면
+    if (num != "")
+    {
+        // 0제거
+        while (num != "0" && num[0] == '0')
+        {
+            num.erase(0, 1);
+        }
+        v.push_back(num);
+    }
+}
+
+bool cmp(string a, string b)
+{
+    // 문자열 길이로 비교
+    if (a.length() != b.length())
+    {
+        return a.length() < b.length();
+    }
+    else
+    {
+        // 길이 같을 시엔 그냥 비교
+        return a < b;
+    }
+}
+
+int main()
+{
+    int n;
+    cin >> n;
+    for (int i = 0; i < n; i++)
+    {
+        string str;
+        cin >> str;
+        go(str);
+    }
+
+    sort(v.begin(), v.end(), cmp);
+
+    for (string s : v)
+    {
+        cout << s << '\n';
+    }
+}
\ No newline at end of file
diff --git a/week2/2910.cpp b/week2/2910.cpp
new file mode 100644
index 0000000..7e84e70
--- /dev/null
+++ b/week2/2910.cpp
@@ -0,0 +1,55 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int N, C;
+
+unordered_map<int, pair<int, int>> m;
+
+bool cmp(pair<int, pair<int, int>> a, pair<int, pair<int, int>> b)
+{
+    if (a.second.first == b.second.first)
+        return a.second.second < b.second.second;
+
+    return a.second.first > b.second.first;
+}
+
+int main()
+{
+    cin >> N >> C;
+    for (int i = 0; i < N; i++)
+    {
+        int num;
+        cin >> num;
+
+        if (m.find(num) != m.end())
+        {
+            m[num].first++;
+        }
+        else
+        {
+            m.insert({num, {1, i}});
+        }
+    }
+
+    vector<pair<int, pair<int, int>>> v(m.begin(), m.end());
+
+    sort(v.begin(), v.end(), cmp);
+
+    for (int i = 0; i < v.size(); i++)
+    {
+        for (int j = 0; j < v[i].second.first; j++)
+        {
+            if (i == v.size() - 1 && j == v[i].second.first - 1)
+            {
+                cout << v[i].first;
+            }
+            else
+            {
+                cout << v[i].first << " ";
+            }
+        }
+    }
+
+    return 0;
+}
\ No newline at end of file
diff --git a/week2/3474.cpp b/week2/3474.cpp
new file mode 100644
index 0000000..a4a1959
--- /dev/null
+++ b/week2/3474.cpp
@@ -0,0 +1,40 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int getCount(int num)
+{
+    int two = 0;
+    int five = 0;
+
+    for (int i = 2; i <= num; i *= 2)
+    {
+        two += num / i;
+    }
+    for (int j = 5; j <= num; j *= 5)
+    {
+        five += num / j;
+    }
+
+    return min(two, five);
+}
+
+int main()
+{
+
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+    cout.tie(NULL);
+
+    int t;
+    cin >> t;
+
+    for (int i = 0; i < t; i++)
+    {
+        int num;
+        cin >> num;
+        cout << getCount(num) << '\n';
+    }
+
+    return 0;
+}
\ No newline at end of file
diff --git a/week2/4659.cpp b/week2/4659.cpp
new file mode 100644
index 0000000..b3cee7f
--- /dev/null
+++ b/week2/4659.cpp
@@ -0,0 +1,88 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+char a[] = {'a', 'e', 'i', 'o', 'u'};
+void check(string s)
+{
+    // first
+    bool first = false;
+    for (int i = 0; i < 5; i++)
+    {
+        if (s.find(a[i]) != string::npos)
+            first = true;
+    }
+
+    if (!first)
+    {
+        cout << "<" << s << "> is not acceptable." << '\n';
+        return;
+    }
+
+    // 2nd
+    if (s.length() >= 3)
+    {
+        string copy = s;
+
+        for (int i = 0; i < copy.length(); i++)
+        {
+            bool isA = false;
+            for (int j = 0; j < 5; j++)
+            {
+                if (copy[i] == a[j])
+                {
+                    isA = true;
+                }
+            }
+
+            if (isA)
+            {
+                copy[i] = 'a';
+            }
+            else
+            {
+                copy[i] = 'b';
+            }
+        }
+
+        if (copy.find("aaa") != string::npos || copy.find("bbb") != string::npos)
+        {
+            cout << "<" << s << "> is not acceptable." << '\n';
+            return;
+        }
+    }
+
+    // 3rd
+    if (s.length() >= 2)
+    {
+        for (int i = 0; i < s.length() - 1; i++)
+        {
+            if (s[i] == s[i + 1])
+            {
+                if (s[i] != 'e' && s[i] != 'o')
+                {
+                    cout << "<" << s << "> is not acceptable." << '\n';
+                    return;
+                }
+            }
+        }
+    }
+
+    cout << "<" << s << "> is acceptable." << '\n';
+    return;
+}
+
+int main()
+{
+    while (1)
+    {
+        string s;
+
+        cin >> s;
+        if (s == "end")
+        {
+            return 0;
+        }
+        check(s);
+    }
+}
\ No newline at end of file
diff --git a/week3/1189.cpp b/week3/1189.cpp
new file mode 100644
index 0000000..75d3674
--- /dev/null
+++ b/week3/1189.cpp
@@ -0,0 +1,72 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int R, C, K;
+
+int a[5][5] = {
+    0,
+};
+
+int visited[5][5] = {
+    0,
+};
+
+int dy[] = {-1, 1, 0, 0};
+int dx[] = {0, 0, -1, 1};
+
+int result = 0;
+
+void dfs(int y, int x, int cnt)
+{
+    if (cnt == K && y == 0 && x == C - 1)
+    {
+        result++;
+        return;
+    }
+
+    for (int i = 0; i < 4; i++)
+    {
+        int ny = y + dy[i];
+        int nx = x + dx[i];
+
+        if (ny < 0 || nx < 0 || ny >= R || nx >= C)
+            continue;
+        if (a[ny][nx] == 0)
+            continue;
+        if (visited[ny][nx] == 1)
+            continue;
+
+        visited[ny][nx] = 1;
+        dfs(ny, nx, cnt + 1);
+        visited[ny][nx] = 0; // 방문해제
+    }
+}
+
+int main()
+{
+
+    cin >> R >> C >> K;
+    for (int i = 0; i < R; i++)
+    {
+        for (int j = 0; j < C; j++)
+        {
+            char c;
+            cin >> c;
+
+            // 갈 수 없는 곳은 0 있는 곳은 1
+            if (c == 'T')
+            {
+                a[i][j] = 0;
+            }
+            else
+            {
+                a[i][j] = 1;
+            }
+        }
+    }
+
+    visited[R - 1][0] = 1;
+    dfs(R - 1, 0, 1);
+    cout << result;
+}
\ No newline at end of file
diff --git a/week3/2589.cpp b/week3/2589.cpp
new file mode 100644
index 0000000..55fdc73
--- /dev/null
+++ b/week3/2589.cpp
@@ -0,0 +1,101 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int N, M;
+char a[50][50] = {
+    'W',
+};
+
+const int dy[] = {-1, 1, 0, 0};
+const int dx[] = {0, 0, -1, 1};
+
+queue<pair<int, int>> q;
+
+int finalMax = 0;
+
+int bfs(int y, int x)
+{
+
+    int visited[50][50] = {
+        0,
+    };
+    int max = 0;
+
+    visited[y][x] = 1;
+    q.push(make_pair(y, x));
+    while (q.size())
+    {
+        tie(y, x) = q.front();
+        q.pop();
+
+        for (int i = 0; i < 4; i++)
+        {
+            int ny = y + dy[i];
+            int nx = x + dx[i];
+
+            if (ny < 0 || nx < 0 || ny >= N || nx >= M)
+                continue;
+            if (visited[ny][nx])
+                continue;
+            if (a[ny][nx] != 'L')
+                continue;
+
+            q.push({ny, nx});
+            visited[ny][nx] = visited[y][x] + 1;
+        }
+    }
+
+    // 현 시작점에서 가장 먼 곳일때 최단 거리 찾기
+    for (int i = 0; i < N; i++)
+    {
+        for (int j = 0; j < M; j++)
+        {
+            if (a[i][j] == 'L')
+            {
+                if (max < visited[i][j])
+                    max = visited[i][j];
+            }
+        }
+    }
+
+    return max - 1;
+}
+
+void go()
+{
+    // 가능한 모든 시작점(육지)에서 모든 육지에 대한 최장거리를 찾기.
+
+    for (int i = 0; i < N; i++)
+    {
+        for (int j = 0; j < M; j++)
+        {
+            if (a[i][j] == 'L')
+            {
+                int temp = bfs(i, j);
+                if (finalMax < temp)
+                {
+                    finalMax = temp;
+                }
+            }
+        }
+    }
+}
+
+int main()
+{
+    cin >> N >> M;
+    for (int i = 0; i < N; i++)
+    {
+        for (int j = 0; j < M; j++)
+        {
+            char c;
+            cin >> c;
+            a[i][j] = c;
+        }
+    }
+
+    go();
+
+    cout << finalMax;
+}