Browse Source

day 9 part 1 solution

main
Colin McMillen 1 year ago
parent
commit
0ba214e030
  1. 76
      2020/Day09.cs
  2. 1000
      2020/day09.txt

76
2020/Day09.cs

@ -0,0 +1,76 @@
using System;
using static System.Console;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;
using Xunit;
namespace AdventOfCode {
public class Day09 {
static bool Valid(List<long> ints, int preambleSize, int target) {
for (int i = target - preambleSize; i < target - 1; i++) {
for (int j = i + 1; j < target; j++) {
if (i == j) {
continue;
}
if (ints[i] + ints[j] == ints[target]) {
return true;
}
}
}
return false;
}
static long FindInvalid(List<long> ints, int preambleSize) {
for (int target = preambleSize; target < ints.Count(); target++) {
if (!Valid(ints, preambleSize, target)) {
return ints[target];
}
}
throw new Exception("didn't find an invalid int");
}
static long Part1() {
string[] input = File.ReadAllLines(Util.RootDir + "day09.txt");
List<long> ints = input.ToList().Select(long.Parse).ToList();
return FindInvalid(ints, 25);
}
static int Part2() {
return -1;
}
[Fact]
public static void Test() {
string[] example =
@"35
20
15
25
47
40
62
55
65
95
102
117
150
182
127
219
299
277
309
576".Split('\n');
List<long> ints = example.ToList().Select(long.Parse).ToList();
Assert.Equal(127, FindInvalid(ints, 5));
Assert.Equal(50047984, Part1());
Assert.Equal(-1, Part2());
}
}
}

1000
2020/day09.txt
File diff suppressed because it is too large
View File

Loading…
Cancel
Save