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 (GCC 5.4.1) (judge verdict: Accepted)

#include <stdio.h>

int main() {
  int N[4];
  int check[4];
  for (int i = 0; i < 4; i++) {
    check[i] = 0;
  }
  scanf("%d %d %d %d",&N[0],&N[1],&N[2],&N[3]);
  for (int i = 0; i < 4; i++) {
    if (N[i] == 1) check[0] = 1;
    if (N[i] == 9) check[1] = 1;
    if (N[i] == 7) check[2] = 1;
    if (N[i] == 4) check[3] = 1;
  }
  for (int i = 0; i < 4; i++) {
    if (check[i] == 0) {
      printf("NO\n");
      return 0;
    }
  }
  printf("YES\n");
  return 0;
}