From 756f22d58bb198b8f34589c112e1003614ccdcd6 Mon Sep 17 00:00:00 2001
From: Thomas Schmucker <ts@its1.de>
Date: Sun, 2 Nov 2025 21:41:58 +0100
Subject: aoc 2017, days 1-20

---
 2017/src/day04.cpp | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 2017/src/day04.cpp

(limited to '2017/src/day04.cpp')

diff --git a/2017/src/day04.cpp b/2017/src/day04.cpp
new file mode 100644
index 0000000..01e89b2
--- /dev/null
+++ b/2017/src/day04.cpp
@@ -0,0 +1,78 @@
+#include <algorithm>
+#include <filesystem>
+#include <fstream>
+#include <iostream>
+#include <set>
+#include <sstream>
+#include <string>
+
+using namespace std;
+
+namespace {
+
+vector<string>
+read_lines(const filesystem::path& filename)
+{
+	ifstream       file{ filename };
+	vector<string> lines;
+
+	for ( string line; getline(file, line); ) {
+		lines.emplace_back(line);
+	}
+
+	return lines;
+}
+
+vector<string>
+split(const string& line)
+{
+	stringstream   strm{ line };
+	vector<string> words;
+
+	for ( string word; strm >> word; ) {
+		words.emplace_back(word);
+	}
+
+	return words;
+}
+
+void
+part1(const vector<string>& lines)
+{
+	auto num = ranges::count_if(lines, [](const string& line) {
+		auto        words = split(line);
+		set<string> set{ words.begin(), words.end() };
+
+		return set.size() == words.size();
+	});
+
+	cout << "Part1: " << num << '\n';
+}
+
+void
+part2(const vector<string>& lines)
+{
+	auto num = ranges::count_if(lines, [](const string& line) {
+		auto        words = split(line);
+		set<string> set;
+
+		for ( auto word: words ) {
+			ranges::sort(word);
+			set.insert(word);
+		}
+
+		return set.size() == words.size();
+	});
+
+	cout << "Part2: " << num << '\n';
+}
+
+} // namespace
+
+int
+main()
+{
+	auto lines = read_lines("data/day04.txt");
+	part1(lines);
+	part2(lines);
+}
-- 
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