65 lines
2.1 KiB
D
65 lines
2.1 KiB
D
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import std;
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void main()
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{
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readText("input").calculateNumberOfContainingBagsTranisitively("shiny gold").writeln;
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}
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auto calculateNumberOfContainingBagsTranisitively(string rules, string color)
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{
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return rules.calculateContainingBagsTranisitively(color).byKey.count;
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}
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auto calculateContainingBagsTranisitively(string rules, string color)
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{
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return rules.parseRules.calculateContainingBagsTranisitively(color);
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}
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void[0][string] calculateContainingBagsTranisitively(string[][string] containedInMap, string color)
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{
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string[]* containingBags = (color in containedInMap);
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if (!containingBags || (*containingBags).length == 0)
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{
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return null;
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}
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void[0][string] result;
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foreach (bag; *containingBags)
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{
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result[bag] = [];
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containedInMap.calculateContainingBagsTranisitively(bag)
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.byKey.each!((containingBag) => result[containingBag] = []);
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}
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return result;
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}
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auto parseRules(string rules)
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{
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string[][string] containedInMap;
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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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auto containingBag = spec[0];
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spec[1].splitter(", ").filter!(it => it != "no other bags.")
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.map!(bagSpec => bagSpec.matchFirst(r"(\d+) (.+) (bag|bags)\.*")[2])
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.each!(bag => containedInMap.update(bag, {
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return [containingBag];
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}, (ref string[] old) { return old ~ [containingBag]; }));
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});
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return containedInMap;
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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.calculateNumberOfContainingBagsTranisitively("shiny gold") == 4);
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}
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