From a8f11c0a8470c4e6b67e70219986712cd70d0de2 Mon Sep 17 00:00:00 2001
From: Thomas Schmucker <ts@its1.de>
Date: Sun, 12 Jan 2025 12:10:42 +0100
Subject: aoc 2016, day 3

---
 2016/src/day02.cpp |  1 -
 2016/src/day03.cpp | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 57 insertions(+), 1 deletion(-)
 create mode 100644 2016/src/day03.cpp

(limited to '2016/src')

diff --git a/2016/src/day02.cpp b/2016/src/day02.cpp
index ad625d5..612de28 100644
--- a/2016/src/day02.cpp
+++ b/2016/src/day02.cpp
@@ -13,7 +13,6 @@ read_file(string_view filename)
 	fstream        input{ filename };
 	vector<string> lines;
 
-	vector<tuple<char, long>> result;
 	for ( string line; getline(input, line); ) {
 		lines.emplace_back(line);
 	}
diff --git a/2016/src/day03.cpp b/2016/src/day03.cpp
new file mode 100644
index 0000000..fad26b8
--- /dev/null
+++ b/2016/src/day03.cpp
@@ -0,0 +1,57 @@
+#include <array>
+#include <fstream>
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <vector>
+
+using namespace std;
+
+vector<array<long, 3>>
+read_file(string_view filename)
+{
+	fstream                input{ filename };
+	vector<array<long, 3>> result;
+
+	for ( string line; getline(input, line); ) {
+		stringstream sstr{ line };
+		vector<long> nums{ istream_iterator<long>{ sstr }, {} };
+
+		result.push_back({ nums.at(0), nums.at(1), nums.at(2) });
+	}
+
+	return result;
+}
+
+bool
+is_triangle(array<long, 3> set)
+{
+	ranges::sort(set);
+	return set[0] + set[1] > set[2];
+}
+
+void
+part1(const vector<array<long, 3>>& data)
+{
+	cout << ranges::count_if(data, is_triangle) << endl;
+}
+
+void
+part2(const vector<array<long, 3>>& data)
+{
+	long sum = 0;
+	for ( size_t row = 0; row < data.size(); row += 3 ) {
+		sum += is_triangle({ data[row][0], data[row + 1][0], data[row + 2][0] }) ? 1 : 0;
+		sum += is_triangle({ data[row][1], data[row + 1][1], data[row + 2][1] }) ? 1 : 0;
+		sum += is_triangle({ data[row][2], data[row + 1][2], data[row + 2][2] }) ? 1 : 0;
+	}
+	cout << sum << endl;
+}
+
+int
+main()
+{
+	auto data = read_file("data/day03.txt");
+	part1(data);
+	part2(data);
+}
-- 
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