Custom Judge example

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include<cmath>
#include <cassert>
using namespace std;


#ifdef LOCAL_TESTING
FILE *spoj_p_in, *spoj_p_out, *spoj_t_out;
#define PIN "0.in"
#define POUT "0.out"
#define TOUT "out.txt"
#define SPOJ_RV_POSITIVE 0
#define SPOJ_RV_NEGATIVE -1
int c = 0;
void spoj_init() {
  spoj_p_in=fopen(PIN,"r");
  spoj_p_out=fopen(POUT, "r");
  spoj_t_out=fopen(TOUT, "r");
}
void spoj_assert(bool t) {
  assert(t);
}
#else
#include<spoj.h>
#endif


char ans[1000000];
void verify(int n, int len)
{
    int n2 = n;
    int cnt = 0;
    int sz = strlen(ans);
    spoj_assert(sz==len);
    for(int i=0;i<sz;i++)
    {
        spoj_assert(ans[i]=='X' || ans[i]=='D');
        if(ans[i]=='X')
            cnt++;
        else
            n-=cnt;
        spoj_assert(n>=0);
    }
    spoj_assert(n==0);
}
int main()
{
    spoj_init();
    int t,tmp;
    tmp = fscanf(spoj_p_in, "%d", &t);
    while(t--)
    {
        int n;
        tmp = fscanf(spoj_p_in, "%d", &n);
        int a = sqrtl(n);
        int b = (n+a-1)/a;
        int len = a+b;
        spoj_assert(fscanf(spoj_t_out, "%s", ans) == 1);
        verify(n,len);
    }
    #ifdef LOCAL_TESTING
    cout<<c;
    #endif
    return SPOJ_RV_POSITIVE;
}