Hackerrank Anagram solution

The below program is the solution of Anagram in implementation sub-domain. You can refer the question from HERE.

Output :

Code :

#include<stdio.h>

int main()
{
    int t,i,x,c,flag;
    char s[10001];
    int *a=(int*)malloc(sizeof(int)*26);
    int *b=(int*)malloc(sizeof(int)*26);
    memset(a,0,sizeof(int)*26);
    memset(b,0,sizeof(int)*26);
    scanf("%d",&t);
    while(t--)
    {
        scanf("%s",&s);
        flag=0;c=0;
        if(strlen(s)%2==1)
        {
            printf("-1\n");
            continue;
        }
        for(i=0;i<26;i++)
        {
            a[i]=b[i]=0;
        }
        for(i=0;i<strlen(s)/2;i++)
            a[s[i]-'a']++;
        for(i=strlen(s)/2;i<strlen(s);i++)
            b[s[i]-'a']++;
        for(i=0;i<26;i++)
        {
            c+=abs(a[i]-b[i]);
        }
        printf("%d\n",c/2);

    }
}