Problem:
Score : 200 points

Problem Statement

You are given a string S consisting of lowercase English letters. Determine whether all the characters in S are different.

Constraints

2 ≤ |S| ≤ 26, where |S| denotes the length of S.

S consists of lowercase English letters.

Input

Input is given from Standard Input in the following format:

S

Output

If all the characters in S are different, print yes (case-sensitive); otherwise, print no.

Sample Input 1

uncopyrightable

Sample Output 1

yes

Sample Input 2

different

Sample Output 2

no

Sample Input 3

no

Sample Output 3

yes

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


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

int main(){
    char S[27];
    int a[27], i, len;

    scanf("%s", S);
    len = strlen(S);

    for(i=0; i<27; i++){
        a[i] = 0;
    }

    for(i=0; i<len; i++){
        if(a[S[i]+'0'] == 0)
            a[S[i]+'0']++;
        else{
            printf("no\n");
            return 0;
        }
    }

    printf("yes\n");
    return 0;
}