Problem:
Score : 200 points

Problem Statement

A string is called a KEYENCE string when it can be changed to keyence by removing its contiguous substring (possibly empty) only once.

Given a string S consisting of lowercase English letters, determine if S is a KEYENCE string.

Constraints

The length of S is between 7 and 100 (inclusive).

S consists of lowercase English letters.

Input

Input is given from Standard Input in the following format:

S

Output

If S is a KEYENCE string, print YES; otherwise, print NO.

Sample Input 1

keyofscience

Sample Output 1

YES

keyence is an abbreviation of key of science.

Sample Input 2

mpyszsbznf

Sample Output 2

NO

Sample Input 3

ashlfyha

Sample Output 3

NO

Sample Input 4

keyence

Sample Output 4

YES

Solution in C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>
#include <string.h>

int main()
{
  int cnt;
  char str[100] = {0,};
  char keyence[] = "keyence";
  int match[7] = {0,};
  int i, j;
  int m_cnt = 0;
  int skip  = 0;
  int m_2nd = 0;
  int len;

  cnt = scanf("%s", str);

  len = strlen(str);

  for (i=0; i<len; i++) {
    for (j=0; j<7; j++) {
      if (match[j] != 0) continue;
      if (keyence[j] == str[i]) {
        match[j] = 1;
        m_cnt++;
        if (skip > 0) {
          m_2nd++;
        }
        break;
      } else {
        if (m_2nd != 0) {
          printf ("NO");
          return 0;
        }
        if (m_cnt > 0) {
          skip++;
        }
        break;
      }
    }//for j

    if (m_cnt == 7) {
      printf ("YES");
      return 0;
    }

  }//for i

  printf ("NO");
  return 0;
}