From 50ffa7beba18811b74945b762a86da3fd5a795e5 Mon Sep 17 00:00:00 2001
From: Thomas Schmucker <ts@its1.de>
Date: Sat, 7 Dec 2024 08:22:16 +0100
Subject: aoc 2024, day 7, part 1

---
 2024/src/day07.cpp | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)
 create mode 100644 2024/src/day07.cpp

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);
+}
-- 
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