33 lines
589 B
D
33 lines
589 B
D
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import std;
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void main()
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{
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File("input", "r").byLine.map!(to!int).array.multiply2EntriesThatSumTo(2020).writeln;
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}
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int multiply2EntriesThatSumTo(int[] input, int sum)
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{
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foreach (key1; input)
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{
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foreach (key2; input)
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{
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if (key2 == key1)
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{
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continue;
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}
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if (key1 + key2 == sum)
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{
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return key1 * key2;
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}
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}
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}
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return 0;
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}
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unittest
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{
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auto input = [1721, 979, 366, 299, 675, 1456];
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assert(input.multiply2EntriesThatSumTo(2020) == 514579);
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}
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