Problem:
Score : 100 points

Problem Statement

You are given four digits N_1, N_2, N_3 and N_4. Determine if these can be arranged into the sequence of digits "1974".

Constraints

0 \leq N_1, N_2, N_3, N_4 \leq 9

N_1, N_2, N_3 and N_4 are integers.

Input

Input is given from Standard Input in the following format:

N_1 N_2 N_3 N_4

Output

If N_1, N_2, N_3 and N_4 can be arranged into the sequence of digits "1974", print YES; if they cannot, print NO.

Sample Input 1

1 7 9 4

Sample Output 1

YES

We can get 1974 by swapping N_2 and N_3.

Sample Input 2

1 9 7 4

Sample Output 2

YES

We already have 1974 before doing anything.

Sample Input 3

1 2 9 1

Sample Output 3

NO

Sample Input 4

4 9 0 8

Sample Output 4

NO

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleAppKEYENCEBeginning
{
    class Program
    {
        static void Main(string[] args)
        {
            // スペース区切りの整数の入力
            string[] input = Console.ReadLine().Split(' ');
            int[] n = new int[input.Count()];
            for(int i = 0; i < input.Count(); i++)
            {
                n[i] = int.Parse(input[i]);
            }
            //
            string ans="NO";
            for(int j = 0; j<input.Count(); j++)
            {
                if(n[j%4]*1000+ n[(j+1)%4]*100+n[(j + 2) % 4] *10+n[(j + 3) % 4] ==1974)
                {
                    ans = "YES";
                }
                if (n[j % 4] * 1000 + n[(j + 1) % 4] * 100 + n[(j + 3) % 4] * 10 + n[(j + 2) % 4] == 1974)
                {
                    ans = "YES";
                }
                if (n[j % 4] * 1000 + n[(j + 2) % 4] * 100 + n[(j + 1) % 4] * 10 + n[(j + 3) % 4] == 1974)
                {
                    ans = "YES";
                }
                if (n[j % 4] * 1000 + n[(j + 2) % 4] * 100 + n[(j + 3) % 4] * 10 + n[(j + 1) % 4] == 1974)
                {
                    ans = "YES";
                }
                if (n[j % 4] * 1000 + n[(j + 3) % 4] * 100 + n[(j + 1) % 4] * 10 + n[(j + 2) % 4] == 1974)
                {
                    ans = "YES";
                }
                if (n[j % 4] * 1000 + n[(j + 3) % 4] * 100 + n[(j + 2) % 4] * 10 + n[(j + 1) % 4] == 1974)
                {
                    ans = "YES";
                }
            }
            Console.WriteLine(ans);
        }
    }
}