aoc 2024, day 11, part 1

1 files changed, 45 insertions, 0 deletions

diff --git a/2024/src/day11.cpp b/2024/src/day11.cpp
new file mode 100644
index 0000000..f31e30b
--- /dev/null
+++ b/2024/src/day11.cpp
@@ -0,0 +1,45 @@
+#include <fstream>
+#include <iostream>
+#include <iterator>
+#include <vector>
+using namespace std;
+
+vector<long>
+read_file(string_view filename)
+{
+        fstream input{ filename };
+        return { istream_iterator<long>{ input }, {} };
+}
+
+void
+part1(vector<long> data)
+{
+        for ( size_t i = 0; i != 25; ++i ) {
+                vector<long> temp;
+                for ( const auto value: data ) {
+                        if ( value == 0 ) {
+                                temp.push_back(1);
+                                continue;
+                        }
+
+                        auto str = to_string(value);
+                        if ( str.size() % 2 == 0 ) {
+                                auto len = str.size() / 2;
+                                temp.push_back(stol(str.substr(0, len)));
+                                temp.push_back(stol(str.substr(len)));
+                                continue;
+                        }
+
+                        temp.push_back(value * 2024);
+                }
+                data.swap(temp);
+        }
+        cout << data.size() << endl;
+}
+
+int
+main()
+{
+        auto data = read_file("data/day11.txt");
+        part1(data);
+}