77 lines
1.5 KiB
C#
77 lines
1.5 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 System.Text.RegularExpressions;
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using Xunit;
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namespace AdventOfCode {
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public class Day09 {
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static bool Valid(List<long> ints, int preambleSize, int target) {
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for (int i = target - preambleSize; i < target - 1; i++) {
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for (int j = i + 1; j < target; j++) {
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if (i == j) {
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continue;
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}
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if (ints[i] + ints[j] == ints[target]) {
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return true;
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}
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}
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}
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return false;
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}
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static long FindInvalid(List<long> ints, int preambleSize) {
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for (int target = preambleSize; target < ints.Count(); target++) {
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if (!Valid(ints, preambleSize, target)) {
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return ints[target];
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}
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}
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throw new Exception("didn't find an invalid int");
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}
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static long Part1() {
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string[] input = File.ReadAllLines(Util.RootDir + "day09.txt");
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List<long> ints = input.ToList().Select(long.Parse).ToList();
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return FindInvalid(ints, 25);
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}
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static int Part2() {
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return -1;
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}
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[Fact]
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public static void Test() {
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string[] example =
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@"35
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20
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15
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25
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47
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40
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62
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55
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65
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95
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102
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117
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150
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182
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127
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219
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299
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277
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309
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576".Split('\n');
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List<long> ints = example.ToList().Select(long.Parse).ToList();
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Assert.Equal(127, FindInvalid(ints, 5));
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Assert.Equal(50047984, Part1());
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Assert.Equal(-1, Part2());
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}
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}
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}
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