1 files changed, 67 insertions, 0 deletions

diff --git a/2025/src/day01.cpp b/2025/src/day01.cpp
new file mode 100644
index 0000000..aa1ea42
--- /dev/null
+++ b/2025/src/day01.cpp
@@ -0,0 +1,67 @@
+#include <filesystem>
+#include <fstream>
+#include <iostream>
+#include <string>
+#include <vector>
+
+using namespace std;
+
+namespace {
+
+vector<string>
+read_file(const filesystem::path& filename)
+{
+        ifstream       file{ filename };
+        vector<string> lines;
+
+        for ( string line; getline(file, line); ) {
+                lines.emplace_back(line);
+        }
+
+        return lines;
+}
+
+void
+part1(const vector<string>& lines)
+{
+        auto zeros = 0;
+        auto pos   = 50;
+
+        for ( const auto& line: lines ) {
+                auto value = stoi(line.substr(1));
+                value %= 100;
+                pos += (line[0] == 'L') ? (100 - value) : value;
+                if ( pos % 100 == 0 ) {
+                        ++zeros;
+                }
+        }
+        cout << "Part 1: " << zeros << '\n';
+}
+
+void
+part2(const vector<string>& lines)
+{
+        auto zeros = 0;
+        auto pos   = 50;
+
+        for ( const auto& line: lines ) {
+                auto value = stoi(line.substr(1));
+                while ( value-- > 0 ) {
+                        pos += (line[0] == 'L') ? 99 : 1;
+                        if ( pos % 100 == 0 ) {
+                                ++zeros;
+                        }
+                }
+        }
+        cout << "Part 2: " << zeros << '\n';
+}
+
+} // namespace
+
+int
+main()
+{
+        auto data = read_file("data/day01.txt");
+        part1(data);
+        part2(data);
+}