59 lines
1.7 KiB
C#
59 lines
1.7 KiB
C#
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using System;
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using static System.Console;
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using System.Collections.Generic;
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using System.IO;
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using System.Linq;
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using Xunit;
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namespace AdventOfCode {
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public class Day01 {
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static int Part1(List<int> numbers) {
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for (var i = 0; i < numbers.Count; i++) {
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for (var j = i + 1; j < numbers.Count; j++) {
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if (numbers[i] + numbers[j] == 2020) {
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return numbers[i] * numbers[j];
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}
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}
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}
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throw new ArgumentException("no pair of numbers summed to 2020");
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}
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static int Part2(List<int> numbers) {
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for (var i = 0; i < numbers.Count; i++) {
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for (var j = i + 1; j < numbers.Count; j++) {
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for (var k = j + 1; k < numbers.Count; k++) {
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if (numbers[i] + numbers[j] + numbers[k] == 2020) {
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return numbers[i] * numbers[j] * numbers[k];
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}
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}
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}
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}
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throw new ArgumentException("no triple of numbers summed to 2020");
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}
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[Fact]
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public static void Test() {
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var emptyInput = new List<int>();
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var bogusInput = new List<int>() {
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111, 222, 333, 444, 555, 666, 777, 888, 999
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};
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var exampleInput = new List<int>() {
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1721, 979, 366, 299, 675, 1456
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};
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var testInput = Util.ReadInts(Util.RootDir + "day01.txt");
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Assert.Throws<ArgumentException>(() => Part1(emptyInput));
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Assert.Throws<ArgumentException>(() => Part1(bogusInput));
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Assert.Equal(514579, Part1(exampleInput));
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Assert.Equal(355875, Part1(testInput));
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Assert.Throws<ArgumentException>(() => Part2(emptyInput));
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Assert.Throws<ArgumentException>(() => Part2(bogusInput));
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Assert.Equal(241861950, Part2(exampleInput));
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Assert.Equal(140379120, Part2(testInput));
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}
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}
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}
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