do day 1

.gitignore

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+a.out
+

main.cpp

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+#include <fstream>
+#include <iostream>
+#include <vector>
+
+struct Data{ char dir; int64_t cnt; };
+
+using std::cout, std::endl, std::vector, std::ifstream;
+
+int64_t part_1(const vector<Data>&);
+int64_t part_2(const vector<Data>&);
+
+int main() {
+  ifstream file{"input/2025-1.txt"};
+  Data line;
+  vector<Data> v;
+  while (file >> line.dir >> line.cnt) {
+    v.push_back(line);
+  }
+  cout << "Part 1: " << part_1(v) << endl;
+  cout << "Part 1: " << part_2(v) << endl;
+}
+
+int64_t part_1(const vector<Data>& v) {
+   int64_t loc{50}, presses{0};
+   for (auto data : v) {
+     if (data.dir == 'L') {
+       loc -= data.cnt % 100;
+     } else {
+       loc += data.cnt % 100;
+     }
+     loc %= 100;
+     if (loc < 0) {
+       loc += 100;
+     }
+     if (loc == 0) {
+       ++presses;
+     }
+   }
+
+  return presses;
+}
+
+int64_t part_2(const vector<Data>& v) {
+   int64_t loc{50}, presses{0};
+   for (auto data : v) {
+     auto last_loc = loc;
+     if (data.dir == 'L') {
+       loc -= data.cnt % 100;
+     } else {
+       loc += data.cnt % 100;
+     }
+     presses += std::abs(data.cnt / 100);
+     if ((loc != last_loc && loc >= 100) || (loc <= 0 && last_loc != 0)) {
+       presses += 1;
+     }
+     loc %= 100;
+     if (loc < 0) {
+       loc += 100;
+     }
+   }
+
+  return presses;
+}

run

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+#!/bin/bash
+
+set -e
+
+g++ main.cpp -std=c++23
+./a.out