SIGSEGV in SBANK

[cvikasreddy]

Code runs perfectly on my laptop, but gives Segmentstion Fault.Please help

/*http://www.spoj.com/problems/SBANK/  */
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
void so(char *a[32],long int first,long int last)
{
    long int pivot,j,i;
    char temp[32];
    if(first<last)
    {
        pivot=first;
        i=first;
        j=last;
        while(i<j)
        {
            while(strcmp(a[i],a[pivot])<=0&&i<last)
                i++;
            while(strcmp(a[j],a[pivot])>0)
                j--;
            if(i<j)
            {
                strcpy(temp,a[i]);
                strcpy(a[i],a[j]);
                strcpy(a[j],temp);
            }
        }
        strcpy(temp,a[pivot]);
        strcpy(a[pivot],a[j]);
        strcpy(a[j],temp);
        so(a,first,j-1);
        so(a,j+1,last);
    }
}
void repeat(char **a,long int n)
{
    long int i=0,b;
    for(;i<n;)
    {
        b=0;
        do
        {
           b++;
           if(b==1)
           {
                printf("%s ",a[i]);
           }
           i++;
        }while(i<n&&strcmp(a[i-1],a[i])==0);
        printf("%ld\n",b);
    }
    printf("\n");
}
int main()
{
    int t;
    long int i,n;
    char **a,x;
    scanf("%d",&t);
    scanf("%c",&x);
    while(t--)
    {
        scanf("%ld",&n);
        scanf("%c",&x);
        a=(char**)malloc(n*sizeof(char));
        for(i=0;i<n;i++)
        {
            a[i]=(char*)malloc(32*sizeof(char));
            scanf("%[^\n]%*c",a[i]);
        }
        printf("\n");
        so(a,0,n-1);
        repeat(a,n);
        free(a);
        for(i=0;i<n;i++)
            free(a[i]);
    }
    return(0);
}