Day 7 Question 2

Day7/Question2/main.cpp

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+#include <algorithm>
+#include <cstdint>
+#include <fstream>
+#include <iostream>
+#include <string>
+#include <vector>
+
+int main() {
+  std::fstream input("input");
+  std::string currentLine = "";
+  uint16_t lineCount = 0, lengthOfALine = 0;
+  uint64_t password = 0;
+
+  // We are skipping the first line since it only tells us
+  // where to start with 'S'
+  std::getline(input, currentLine, '\n');
+  lengthOfALine = currentLine.length();
+  std::vector<uint64_t> beams(lengthOfALine, 0);
+  beams[currentLine.find('S')] = 1;
+
+  // Each path the beam went now *sigh*
+  while (std::getline(input, currentLine, '\n')) {
+    // Ignore useless middle lines
+    if (lineCount % 2 == 1) {
+      for (int16_t position = 0; position < lengthOfALine; position++) {
+        if (currentLine[position] == '^' && beams[position]) {
+          // Basically idea is to pass the possible timelines to the split beams
+          beams[std::max(position - 1, 0)] += beams[position];
+          beams[std::min(position + 1, static_cast<int>(lengthOfALine))] +=
+              beams[position];
+          beams[position] = 0;
+        }
+      }
+    }
+    lineCount++;
+  }
+
+  // Let's see how many possible timelines were able to reach at the end
+  for (uint64_t val : beams) {
+    password += val;
+  }
+
+  std::cout << password << std::endl;
+}