HR:Sorting_Array_of_Strings.c

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

int count_distinct_characters(const char *a)
{
    int count = 0;
    int char_seen[26] = {0}; // Array to track seen characters ('a' to 'z')

    for (int i = 0; a[i] != '\0'; i++)
    {
        if (!char_seen[a[i] - 'a']) // If character not seen before
        {
            char_seen[a[i] - 'a'] = 1;
            count++;
        }
    }
    return count;
}

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);
}

int sort_by_number_of_distinct_characters(const char *a, const char *b)
{
    int count_a = count_distinct_characters(a);
    int count_b = count_distinct_characters(b);
    if (count_a == count_b)
        return lexicographic_sort(a, b);
    return count_a - count_b;
}

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

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

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");
}