[백준 / C#] 1931 : 회의실 배정

using System;
using System.Linq;

class Program
{
    static int n;
    static int result = 1;
    static void Input()
    {
        n = int.Parse(Console.ReadLine());
    }
    static void Solution()
    {
        int[][] meeting_time = new int[n][];
        for (int i = 0; i < n; i++)
        {
            var input = Console.ReadLine().Split();
            int[] copy = new int[2];
            copy[0] = int.Parse(input[0]);
            copy[1] = int.Parse(input[1]);
            meeting_time[i] = copy;
        }
        // 가변배열 열정렬
        IOrderedEnumerable<int[]> sortedBySecond = meeting_time.OrderBy(y => y[1]).ThenBy(y=> y[0]);
        meeting_time = sortedBySecond.ToArray();
        Compare(meeting_time, 0);
        Console.WriteLine(result);
    }
    static void Compare(int[][] arr, int index)
    {
        int left = 0;
        int right = 1;
        while (right < n)
        {
            int[] leftArr = arr[left];
            int[] nextArr = arr[right];
            if (leftArr[1] > nextArr[0])
                right++;
            else
            {
                leftArr = nextArr;
                left=right++;
                result++;
            }
        }
    }
    static void Solve()
    {
        Input();
        Solution();
    }
    static void Main(string[] args)
    {
        Solve();
    }
}