aoc 2024, day 7, part 1

1 files changed, 62 insertions, 0 deletions

diff --git a/2024/src/day07.cpp b/2024/src/day07.cpp
new file mode 100644
index 0000000..9b16b76
--- /dev/null
+++ b/2024/src/day07.cpp
@@ -0,0 +1,62 @@
+#include <fstream>
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <tuple>
+#include <vector>
+using namespace std;
+
+vector<tuple<long, vector<long>>>
+read_file(string_view filename)
+{
+        fstream input{ filename };
+
+        vector<tuple<long, vector<long>>> data;
+        for ( string line; getline(input, line); ) {
+                auto pos = line.find(':');
+
+                stringstream str{ line.substr(pos + 1) };
+                data.emplace_back(stol(line.substr(0, pos)), vector<long>{ istream_iterator<long>{ str }, {} });
+        }
+        return data;
+}
+
+bool
+can_evaluated(long first, const vector<long>& values)
+{
+        for ( unsigned long pattern = 0; pattern != (1U << (values.size() - 1)); ++pattern ) {
+                long result = values.at(0);
+                for ( size_t idx = 1; idx < values.size(); ++idx ) {
+                        if ( (pattern & (1U << (idx - 1))) == 0 ) {
+                                result += values.at(idx);
+                        }
+                        else {
+                                result *= values.at(idx);
+                        }
+                }
+                if ( first == result ) {
+                        return true;
+                }
+        }
+        return false;
+}
+
+void
+part1(const vector<tuple<long, vector<long>>>& data)
+{
+        long sum = 0;
+        for ( const auto& [first, values]: data ) {
+                if ( can_evaluated(first, values) ) {
+                        sum += first;
+                }
+        }
+        cout << sum << endl;
+}
+
+int
+main()
+{
+        auto data = read_file("data/day07.txt");
+
+        part1(data);
+}