SortingArrayOfStrings.c

// Question link - https://www.hackerrank.com/challenges/sorting-array-of-strings/problem?isFullScreen=true

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int lexicographic_sort(const char* a, const char* b) {
    return strcmp(a,b);
}

int lexicographic_sort_reverse(const char* a, const char* b) {
    return strcmp(b,a);
}

//count distinct character 
int character_count(const char *s){
    int n = 0;
    int count[128] = {0};
    if (NULL == s){
        return -1;
    }
    
    while (*s != '\0') {
        if (!count[*s]){
            count[*s]++;
            n++;
        }
        s++;
    }
    return n;
}



int sort_by_number_of_distinct_characters(const char* a, const char* b) {
    int con = character_count(a) - character_count(b);
    return (con ? con : lexicographic_sort(a, b));
}

int sort_by_length(const char* a, const char* b) {
    int len = strlen(a) - strlen(b);
    return (len ? len : lexicographic_sort(a, b));
}

void string_sort(char** arr,const int len,int (*cmp_func)(const char* a, const char* b)){
    int con = 0;
    while(!con){
        con = 1;
        for (int i = 0; i < len - 1; i++){
            if (cmp_func(arr[i], arr[i+1]) > 0){
                char *temp = arr[i];
                arr[i] = arr [i+1];
                arr[i + 1] = temp;
                con = 0;
            }
        }
    }
}


int main() 
{
    int n;
    scanf("%d", &n);
  
    char** arr;
	arr = (char**)malloc(n * sizeof(char*));
  
    for(int i = 0; i < n; i++){
        *(arr + i) = malloc(1024 * sizeof(char));
        scanf("%s", *(arr + i));
        *(arr + i) = realloc(*(arr + i), strlen(*(arr + i)) + 1);
    }
  
    string_sort(arr, n, lexicographic_sort);
    for(int i = 0; i < n; i++)
        printf("%s\n", arr[i]);
    printf("\n");

    string_sort(arr, n, lexicographic_sort_reverse);
    for(int i = 0; i < n; i++)
        printf("%s\n", arr[i]); 
    printf("\n");

    string_sort(arr, n, sort_by_length);
    for(int i = 0; i < n; i++)
        printf("%s\n", arr[i]);    
    printf("\n");

    string_sort(arr, n, sort_by_number_of_distinct_characters);
    for(int i = 0; i < n; i++)
        printf("%s\n", arr[i]); 
    printf("\n");
}