solve(day 2): Red nosed reports part 1

Makefile

@@ -1,7 +1,4 @@
-# Specify the compiler
 CXX = g++
-
-# Compilation flags
 CXXFLAGS = -std=c++20 -Wall -O2
 
 # Target to compile and run a specific file

day-2/01.cpp

@@ -0,0 +1,87 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+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;
+
+    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);
+        }
+
+        int isInc = 0;  // false by default
+
+        uint lPointer = 0;
+        uint rPointer = 1;
+
+        for (int num : levels) {
+            cout << num << ' ';
+        }
+
+        cout << '\n';
+
+        // We know each level has m numbers
+        while (rPointer < levels.size()) {
+            int diff = levels.at(lPointer) - levels.at(rPointer);
+
+            // If in the first iteration and diff is positive, means we're
+            // increasing
+            if (lPointer == 0) {
+                isInc = diff > 0;
+            }
+
+            // If we've determined it to be increasing, but diff shows
+            // otherwise, means this level will never be safe.
+            // Same for decreasing.
+            if ((isInc && diff < 0) || (!isInc && diff > 0)) {
+                break;
+            }
+
+            // If the diff is not in the range (1 - 3), it is unsafe
+            if (abs(diff) < 1 || abs(diff) > 3) {
+                break;
+            }
+
+            lPointer++;
+            rPointer++;
+        }
+
+        // Means the levels stayed safe
+        if (rPointer == levels.size()) {
+            safeLevels++;
+        }
+    }
+
+    cout << "safe levels: " << safeLevels << '\n';
+
+    return 0;
+}