49 lines
1.6 KiB
D
49 lines
1.6 KiB
D
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import std;
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void main()
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{
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readText("input").calculateNumberOfRequiredBags("shiny gold").writeln;
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}
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auto calculateNumberOfRequiredBags(string rules, string bag)
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{
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return rules.parseRules.calculateNumberOfRequiredBags(bag) - 1;
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}
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int calculateNumberOfRequiredBags(Tuple!(int, string)[][string] containmentMap, string bag)
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{
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return 1 + containmentMap[bag].map!(containedBag => containedBag[0]
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* containmentMap.calculateNumberOfRequiredBags(containedBag[1])).sum;
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}
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auto parseRules(string rules)
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{
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Tuple!(int, string)[][string] containmentMap;
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rules.splitter("\n").filter!(not!empty)
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.each!((rule) {
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auto spec = rule.split(" bags contain ");
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containmentMap[spec[0]] = spec[1].splitter(", ").filter!(it => it != "no other bags.")
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.map!((bagSpec) {
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auto match = bagSpec.matchFirst(r"(\d+) (.+) (bag|bags)\.*");
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return tuple(match[1].to!int, match[2]);
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})
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.array;
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});
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return containmentMap;
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}
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unittest
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{
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auto input = `light red bags contain 1 bright white bag, 2 muted yellow bags.
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dark orange bags contain 3 bright white bags, 4 muted yellow bags.
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bright white bags contain 1 shiny gold bag.
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muted yellow bags contain 2 shiny gold bags, 9 faded blue bags.
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shiny gold bags contain 1 dark olive bag, 2 vibrant plum bags.
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dark olive bags contain 3 faded blue bags, 4 dotted black bags.
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vibrant plum bags contain 5 faded blue bags, 6 dotted black bags.
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faded blue bags contain no other bags.
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dotted black bags contain no other bags.`;
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assert(input.calculateNumberOfRequiredBags("shiny gold") == 32);
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}
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