40 lines
982 B
C#
40 lines
982 B
C#
namespace aoc2019;
|
|
|
|
public sealed class Day04 : Day
|
|
{
|
|
private readonly int start, end;
|
|
|
|
public Day04() : base(4, "Secure Container")
|
|
{
|
|
var range = Input.First().Split('-').Select(int.Parse).ToList();
|
|
start = range[0];
|
|
end = range[1];
|
|
}
|
|
|
|
private bool IsValid(int i)
|
|
{
|
|
var prev = 0;
|
|
var hasDup = false;
|
|
foreach (var curr in i.ToString().Select(c => c - '0'))
|
|
{
|
|
if (curr < prev) return false;
|
|
if (curr == prev) hasDup = true;
|
|
prev = curr;
|
|
}
|
|
|
|
return i >= start && i <= end && hasDup;
|
|
}
|
|
|
|
private bool HasOnePair(int i)
|
|
{
|
|
var s = i.ToString();
|
|
return IsValid(i) && s.Select(c => s.Count(j => j == c)).Any(c => c == 2);
|
|
}
|
|
|
|
public override string Part1() =>
|
|
$"{Enumerable.Range(start, end).Count(IsValid)}";
|
|
|
|
public override string Part2() =>
|
|
$"{Enumerable.Range(start, end).Count(HasOnePair)}";
|
|
}
|