From 631aadb1508a884e8e6667d8ab22399525200d78 Mon Sep 17 00:00:00 2001
From: Thomas Schmucker <ts@its1.de>
Date: Fri, 15 Dec 2023 08:54:08 +0100
Subject: Lösung für Tag 15, Teil 1
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---
 makefile      |  3 ++-
 src/day15.cpp | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 64 insertions(+), 1 deletion(-)
 create mode 100644 src/day15.cpp

diff --git a/makefile b/makefile
index e57b256..87d8aee 100644
--- a/makefile
+++ b/makefile
@@ -13,7 +13,8 @@ all: bin/day01 \
 	 bin/day11 \
 	 bin/day12 \
 	 bin/day13 \
-	 bin/day14
+	 bin/day14 \
+	 bin/day15
 
 bin:
 	mkdir $@
diff --git a/src/day15.cpp b/src/day15.cpp
new file mode 100644
index 0000000..905110f
--- /dev/null
+++ b/src/day15.cpp
@@ -0,0 +1,62 @@
+#include <fstream>
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <vector>
+using namespace std;
+
+string
+read_file(string_view filename)
+{
+	fstream input{ filename };
+	return { istreambuf_iterator<char>{ input }, istreambuf_iterator<char>{} };
+}
+
+inline string&
+rtrim(string& s, const char* t = " \t\n\r\f\v")
+{
+	s.erase(s.find_last_not_of(t) + 1);
+	return s;
+}
+
+vector<string>
+split(const string& line, char sep)
+{
+	vector<string> parts{};
+	stringstream   input{ line };
+
+	for ( string part; getline(input, part, sep); ) {
+		parts.emplace_back(rtrim(part));
+	}
+
+	return parts;
+}
+
+unsigned int
+calculate_hash(string_view str)
+{
+	unsigned int value = 0;
+	for ( auto chr: str ) {
+		value += static_cast<unsigned char>(chr);
+		value *= 17;
+	}
+	return value % 256;
+}
+
+void
+part1()
+{
+	const auto line  = read_file("data/day15.txt");
+	const auto parts = split(line, ',');
+	unsigned long value = 0;
+	for ( const auto& part: parts ) {
+		value += calculate_hash(part);
+	}
+	cout << value << endl;
+}
+
+int
+main()
+{
+	part1();
+}
-- 
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