solve(day 2): Red nosed reports part 2

day-1/01.cpp

@@ -1,9 +1,9 @@
 #include <bits/stdc++.h>
+
 #include "types.hpp"
 
 using namespace std;
 
-
 int main() {
     ios::sync_with_stdio(0);
     cin.tie(0);
@@ -25,7 +25,7 @@ int main() {
     // Build both lists from input
     while (inputFile >> l1 >> l2) {
         cout << "l1: " << l1 << " l2: " << l2 << '\n';
-        
+
         list1.push_back(l1);
         list2.push_back(l2);
     }
@@ -40,7 +40,7 @@ int main() {
     // Compare each element and sum absolute diff (both lists are same size)
     ll diff = 0;
 
-    for (size_t i = 0; i < list1.size(); i++) {
+    for (int i = 0; i < list1.size(); i++) {
         diff += abs(list1[i] - list2[i]);
     }
 

day-2/02.cpp

@@ -0,0 +1,88 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+bool isLevelSafe(vector<int> levels) {
+    bool isIncreasing = true;
+    bool isDecreasing = true;
+
+    for (size_t i = 1; i < levels.size(); i++) {
+        int curr = levels.at(i);
+        int prev = levels.at(i - 1);
+
+        int diff = curr - prev;
+
+        // It cannot be safe since it isn't within bounds
+        if (prev == curr) return false;
+
+        // Bounds is [1, 3]
+        if (abs(diff) > 3) return false;
+
+        if (curr > prev) isDecreasing = false;
+        if (prev > curr) isIncreasing = false;
+    }
+
+    // Must either be increasing or decreasing
+    return isIncreasing || isDecreasing;
+}
+
+// Safety dampener into consideration
+bool isDampenedLevelSafe(vector<int> levels) {
+    if (isLevelSafe(levels)) {
+        return true;
+    }
+
+    for (size_t i = 0; i < levels.size(); i++) {
+        vector<int> remaining = levels;
+        remaining.erase(remaining.begin() + i);
+
+        if (isLevelSafe(remaining)) return true;
+    }
+
+    // If we get here, the level can never be safe
+    return false;
+}
+
+int main() {
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+
+    string filename = "";
+
+    // Prompt for filename
+    cout << "Input File: ";
+    cout.flush();
+
+    // Read in file name
+    getline(cin, filename);
+
+    // Read input from file
+    ifstream inputFile("day-2/" + filename);
+    if (!inputFile.is_open()) {
+        cerr << "Unable to read file\n";
+
+        return 1;
+    }
+
+    // We are reading an n x m input list
+    string line = "";
+
+    int safeLevels = 0;
+
+    // Analyze each level
+    while (getline(inputFile, line)) {
+        vector<int> levels;
+        stringstream stream(line);
+
+        int num;
+
+        // Read each num into the vector
+        while (stream >> num) levels.push_back(num);
+
+        if (isDampenedLevelSafe(levels)) safeLevels++;
+    }
+
+    cout << "safe levels: " << safeLevels << '\n';
+
+    return 0;
+}