64 lines
1.4 KiB
C#
64 lines
1.4 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 Day03 {
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static int CountTreeIntersections(string[] lines, int dx, int dy) {
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int count = 0;
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int x = 0;
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int y = 0;
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while (y < lines.Length - 1) {
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x += dx;
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y += dy;
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string line = lines[y];
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char tile = line[x % line.Length];
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if (tile == '#') {
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count++;
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}
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}
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return count;
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}
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static int Part1() {
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string[] input = File.ReadAllLines(Util.RootDir + "day03.txt");
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return CountTreeIntersections(input, 3, 1);
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}
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static long Part2() {
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string[] input = File.ReadAllLines(Util.RootDir + "day03.txt");
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long result = CountTreeIntersections(input, 1, 1);
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result *= CountTreeIntersections(input, 3, 1);
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result *= CountTreeIntersections(input, 5, 1);
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result *= CountTreeIntersections(input, 7, 1);
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result *= CountTreeIntersections(input, 1, 2);
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return result;
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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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@"..##.......
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#...#...#..
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.#....#..#.
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..#.#...#.#
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.#...##..#.
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..#.##.....
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.#.#.#....#
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.#........#
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#.##...#...
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#...##....#
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.#..#...#.#".Split('\n');
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Assert.Equal(7, CountTreeIntersections(example, 3, 1));
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Assert.Equal(218, Part1());
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Assert.Equal(3847183340, Part2());
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}
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}
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}
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