2025 day 1: solve part 2

Author: yut23

2025/answer_tests/day01/example1.txt

@@ -1,2 +1,3 @@
 Day 1:
 3
+6

2025/src/day01.cpp

@@ -14,18 +14,32 @@ int main(int argc, char **argv) {
     std::ifstream infile = aoc::parse_args(argc, argv).infile;
 
     auto rotations = aoc::day01::read_input(infile);
+    int dial, part1, part2;
 
-    int dial = 50;
-    int part1 = 0;
+    dial = 50;
+    part1 = 0;
     for (const auto rot : rotations) {
         dial += rot;
         dial %= 100;
         if (dial == 0) {
             ++part1;
         }
     }
-
     std::cout << part1 << "\n";
 
+    dial = 50;
+    part2 = 0;
+    for (const auto rot : rotations) {
+        int direction = rot < 0 ? -1 : 1;
+        for (int i = 0; i < std::abs(rot); ++i) {
+            dial += direction;
+            dial %= 100;
+            if (dial == 0) {
+                ++part2;
+            }
+        }
+    }
+    std::cout << part2 << "\n";
+
     return 0;
 }