Solve 2024 day 6 part 1

2024/day-06/main.cpp

@@ -0,0 +1,82 @@
+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+void readInput(vector<string> &mappedArea, pair<int, int> &startingPosition)
+{
+    string line;
+    for (size_t rowIndex = 0; getline(cin, line); rowIndex++) {
+        for (size_t colIndex = 0; colIndex < line.size(); colIndex++) {
+            if (line[colIndex] == '^') {
+                startingPosition = {rowIndex, colIndex};
+            }
+        }
+        mappedArea.push_back(line);
+    }
+}
+
+bool takeStep(vector<string> &mappedArea,
+              pair<int, int> &currentPosition,
+              int &currentOrientation,
+              int &distinctPositionCount)
+{
+    pair<int, int> nextPosition = currentPosition;
+
+    switch (currentOrientation) {
+    case 0:
+        nextPosition.first--;
+        break;
+    case 1:
+        nextPosition.second++;
+        break;
+    case 2:
+        nextPosition.first++;
+        break;
+    case 3:
+        nextPosition.second--;
+        break;
+    default:
+        break;
+    }
+
+    if ((nextPosition.first >= mappedArea.size() || nextPosition.first < 0)
+        || (nextPosition.second >= mappedArea.front().size() || nextPosition.second < 0)) {
+        mappedArea[currentPosition.first][currentPosition.second] = '#';
+        return false;
+    }
+
+    if (mappedArea[nextPosition.first][nextPosition.second] == '#') {
+        currentOrientation = ++currentOrientation % 4;
+        return takeStep(mappedArea, currentPosition, currentOrientation, distinctPositionCount);
+    }
+
+    distinctPositionCount += !(mappedArea[nextPosition.first][nextPosition.second] == 'X');
+
+    mappedArea[currentPosition.first][currentPosition.second] = 'X';
+    mappedArea[nextPosition.first][nextPosition.second] = '^';
+
+    currentPosition = nextPosition;
+    return true;
+}
+
+int main()
+{
+    vector<string> mappedArea;
+    pair<int, int> currentPosition;
+    readInput(mappedArea, currentPosition);
+
+    int currentOrientation = 0;
+    int distinctPositionCount = 1;
+    while (takeStep(mappedArea, currentPosition, currentOrientation, distinctPositionCount))
+        ;
+
+    for (auto row : mappedArea) {
+        cout << row << endl;
+    }
+    cout << endl;
+
+    // Part one
+    cout << "How many distinct positions will the guard visit before leaving the mapped area? "
+         << distinctPositionCount << endl;
+}