Custom Judge - Challenge problem

#include "spoj.h"
#include <iostream>
#include <string>

using namespace std;

char temp1[200];
string Si[10001];
int n, len, P[10001], x, F[10001], S[1000001], sum1;

int main()
{

    spoj_init();

    fscanf(spoj_p_in, "%d", &n);
    spoj_assert(n=10000);

    for (int i = 1; i <= n; ++i) {
        fscanf(spoj_p_in, "%s", temp1);
        Si[i] = temp1;
        len += Si[i].length();
    }

    spoj_assert(len==1000000);

    for(int i=1;i<= len;i++)
    {
        fscanf(spoj_t_out, "%d", &x);
        spoj_assert( (1<=x) && (x <=n) );
        F[x]++;
        spoj_assert(F[x]<=Si[x].length());
        S[i] = (Si[x][F[x]-1] - '0');
    }

    for(int i=1;i<=n;i++)
    {
        spoj_assert(F[i] == Si[i].length());
    }

    for(int i=2;i<=len;i++)
    {
        sum1 += ( (S[i] - S[i-1]) * (S[i] - S[i-1]) );
    }


    fprintf(spoj_score,"%d\n", sum1);

    return SPOJ_RV_POSITIVE;
}