Permutations of Strings in C

Sample Input 0
2
ab
cd

Sample Output 0
ab cd
cd ab

Sample Input 1
3
a
bc
bc

Sample Output 1
a bc bc
bc a bc
bc bc a

Solution in C:-

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

int next_permutation(int n, char **s){

    // Find non-increasing suffix

    int i = n-1;

    while(i>0 && strcmp(s[i-1],s[i])>=0)
        i--;    // find key

    if (i<=0) return 0;

    // Swap key with its successor in suffix

    int j = n-1;
    while(strcmp(s[i-1],s[j])>=0)

        j--;    // find rightmost successor to key

    char *tmp = s[i-1];
    s[i-1] = s[j];
    s[j] = tmp;

    // Reverse the suffix
    j = n-1;

    while(i<j) {

        tmp = s[i];
        s[i] = s[j];
        s[j] = tmp;
        i++;
        j--;
    }
    return 1;
}

int main()
{
    char **s;
    int n;
    scanf("%d", &n);
    s = calloc(n, sizeof(char*));
    for (int i = 0; i < n; i++)

    {
        s[i] = calloc(11, sizeof(char));
        scanf("%s", s[i]);
    }
    do
    {

        for (int i = 0; i < n; i++)
            printf("%s%c", s[i], i == n - 1 ? '\n' : ' ');

    }
 while (next_permutation(n, s));
    for (int i = 0; i < n; i++)
        free(s[i]);
    free(s);
    return 0;
}