From 175f15fba4f9605e17f5ae963beb52681849e702 Mon Sep 17 00:00:00 2001
From: Thomas Schmucker <ts@its1.de>
Date: Tue, 19 Dec 2023 19:47:24 +0100
Subject: Lösungen für Tag 19, Teil 1
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---
 src/day19.cpp | 123 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 123 insertions(+)
 create mode 100644 src/day19.cpp

(limited to 'src')

diff --git a/src/day19.cpp b/src/day19.cpp
new file mode 100644
index 0000000..3dbae22
--- /dev/null
+++ b/src/day19.cpp
@@ -0,0 +1,123 @@
+#include <fstream>
+#include <iostream>
+#include <map>
+#include <regex>
+#include <string>
+#include <vector>
+using namespace std;
+
+string
+read_file(string_view filename)
+{
+	fstream input{ filename };
+	return { istreambuf_iterator<char>{ input }, istreambuf_iterator<char>{} };
+}
+
+vector<string>
+split(string_view line, string_view delimiter)
+{
+	size_t pos_start = 0;
+	size_t pos_end   = 0;
+
+	vector<string> res;
+
+	while ( (pos_end = line.find(delimiter, pos_start)) != std::string::npos ) {
+		auto token = line.substr(pos_start, pos_end - pos_start);
+		pos_start  = pos_end + delimiter.length();
+
+		res.emplace_back(token);
+	}
+
+	if ( pos_start != line.size() ) {
+		res.emplace_back(line.substr(pos_start));
+	}
+	return res;
+}
+
+void
+part1()
+{
+	const auto input        = split(read_file("data/day19.txt"), "\n\n");
+	const auto rules_string = split(input[0], "\n");
+	const auto parts        = split(input[1], "\n");
+
+	const regex rules_pattern{ R"((.*)\{(.*),(.*)\})" };
+	const regex sub_rules_pattern{ R"((.)(.)(\d*):(.*))" };
+
+	map<string, tuple<vector<tuple<string, string, long, string>>, string>> rules;
+
+	for ( const auto& rule: rules_string ) {
+		smatch smatch;
+		if ( regex_search(rule, smatch, rules_pattern) ) {
+			string rule_name    = smatch[1];
+			string default_dest = smatch[3];
+
+			vector<tuple<string, string, long, string>> foo;
+
+			for ( const auto& sub_rule: split(smatch[2].str(), ",") ) {
+				std::smatch smatch2;
+				if ( regex_search(sub_rule, smatch2, sub_rules_pattern) ) {
+					foo.emplace_back(smatch2[1], smatch2[2], stol(smatch2[3]), smatch2[4]);
+				}
+			}
+
+			rules[rule_name] = make_tuple(foo, default_dest);
+		}
+	}
+
+	long sum = 0;
+	const regex parts_pattern{ R"(\{x=(\d*),m=(\d*),a=(\d*),s=(\d*)\})" };
+	for ( const auto& part: parts ) {
+		smatch smatch;
+		if ( regex_search(part, smatch, parts_pattern) ) {
+			const auto xval = stol(smatch[1]);
+			const auto mval = stol(smatch[2]);
+			const auto aval = stol(smatch[3]);
+			const auto sval = stol(smatch[4]);
+
+			string rule = "in";
+			while ( rule != "A" && rule != "R" ) {
+				auto sub_rules = get<0>(rules[rule]);
+				auto next_rule = get<1>(rules[rule]);
+
+				for ( auto sub_rule: sub_rules ) {
+					const auto field = get<0>(sub_rule);
+					const auto cmp   = get<1>(sub_rule);
+					const auto value = get<2>(sub_rule);
+
+					if ( field == "x" && ((cmp == ">" && xval > value) || (cmp == "<" && xval < value)) ) {
+						next_rule = get<3>(sub_rule);
+						break;
+					}
+					if ( field == "m" && ((cmp == ">" && mval > value) || (cmp == "<" && mval < value)) ) {
+						next_rule = get<3>(sub_rule);
+						break;
+					}
+					if ( field == "a" && ((cmp == ">" && aval > value) || (cmp == "<" && aval < value)) ) {
+						next_rule = get<3>(sub_rule);
+						break;
+					}
+					if ( field == "s" && ((cmp == ">" && sval > value) || (cmp == "<" && sval < value)) ) {
+						next_rule = get<3>(sub_rule);
+						break;
+					}
+				}
+
+				rule = next_rule;
+			}
+			if (rule == "A") {
+				sum += xval;
+				sum += mval;
+				sum += aval;
+				sum += sval;
+			}
+		}
+	}
+	cout << sum << endl;
+}
+
+int
+main()
+{
+	part1();
+}
-- 
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