55 lines
1.3 KiB
C#
55 lines
1.3 KiB
C#
using System;
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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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namespace aoc2019
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{
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internal class Day4 : Day
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{
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int start, end;
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public Day4()
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{
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var range = File.ReadLines("input/day4.in")
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.First()
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.Split('-')
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.Select(i => int.Parse(i))
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.ToList();
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start = range[0]; end = range[1];
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}
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private bool IsValid(int i)
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{
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int prev = 0; bool hasDup = false;
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foreach (var c in i.ToString())
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{
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int curr = c - '0';
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if (curr < prev) return false;
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if (curr == prev) hasDup = true;
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prev = curr;
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}
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return i >= start && i <= end && hasDup;
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}
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public override void Part1()
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{
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Console.WriteLine(Enumerable.Range(start, end).Count(i => IsValid(i)));
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}
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private bool HasOnePair(int i)
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{
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var s = i.ToString();
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return s.Select(c => s.Count(j => j == c)).Any(c => c == 2);
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}
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public override void Part2()
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{
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Console.WriteLine(Enumerable.Range(start,end).Count(i => IsValid(i) && HasOnePair(i)));
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}
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}
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}
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