Create BOJ11505.cpp

Author: meenyweeny

Segment Tree/BOJ11505.cpp

@@ -0,0 +1,91 @@
+#include<iostream>
+using namespace std;
+
+const int mod = 1e9 + 7;
+const int nodesize = 1e6 + 1;
+unsigned long long tree[nodesize << 2];
+int n, m, k;
+int unit;
+
+void getUnit() {
+    unit = 2;
+    while (1) {
+        if (unit >= n) {
+            break;
+        }
+        unit *= 2;
+    }
+}
+
+void input() {
+    cin >> n >> m >> k;
+    getUnit();
+    fill(tree, tree + (nodesize << 2), 1);
+    for (int i = 0; i < n; i++) {
+        cin >> tree[i+unit];
+    }
+}
+
+void buildTree() {
+    for (int i = unit - 1; i > 0; i--) {
+        tree[i] = (tree[i * 2] * tree[i * 2 + 1]);
+        tree[i] %= mod;
+    }
+}
+
+void update(int index, int value) {
+    --index; index += unit;
+    unsigned long long before = tree[index];
+    tree[index] = value;
+    index /= 2;
+    while (index > 0) {
+        tree[index] = tree[index * 2] * tree[index * 2 + 1];
+        tree[index] %= mod;
+        index /= 2;
+    }
+}
+
+unsigned long long query(int start, int end) {
+    unsigned long long answer = 1;
+    if (start > end) swap(start, end);
+    start--; end--; start += unit; end += unit;
+    while (start <= end) {
+        if (start % 2) {
+            answer *= tree[start];
+            answer %= mod;
+            ++start;
+        }
+        if (!(end % 2)) {
+            answer *= tree[end];
+            answer %= mod;
+            --end;
+        }
+        start /= 2;
+        end /= 2;
+    }
+    return answer;
+}
+
+void solve() {
+    input();
+    buildTree();
+    int cmd, b, c;
+    m += k;
+    while (m--) {
+        cin >> cmd >> b >> c;
+        if (cmd == 1) {
+            update(b, c);
+        } else {
+            cout << query(b, c) << '\n';
+        }
+    }
+}
+
+int main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+    cout.tie(NULL);
+
+    solve();
+    return 0;
+}