Here you will find solutions of many problems on spoj. If you want solution of some problem which is not listed in blog or have doubt regarding any spoj problem (which i have solved) or any programming concept (data structure) you can mail me @ raj.nishant360@gmail.com
And my humble request to you all that don't copy the code only try to understand the logic and algorithm behind the code. I have started this because if you tried as hard as you can and still can't find any solution to the problem then you can refer to this.
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Monday, November 24, 2014

TESSER-Finding the Tesserect

Finding the Tesserect

Given below c++ code is for TESSER spoj or Finding the tesserect spoj.

Hint:- Use hashing or suffix array to find pattern in difference string.



#include <bits/stdc++.h>
using namespace std;
#define ULL unsigned long long
ULL hash[100009];
#define MU 123
void preHash(char str[] , int n)
{
    hash[n] = 0;
    for(int i = n-1 ; i>=0 ; i--)
        hash[i] = hash[i+1]*MU + str[i] - 65;
}
void solve(char str[] ,char pattern[] , int n , int m)
{
    ULL phv = 0;//hash value for pattern strings
    ULL multiplier = 1;
    for(int i = m-1 ; i>=0 ; i--){
        phv = phv*MU + pattern[i] - 65;
        multiplier = multiplier*MU;
    }
    preHash(str , n);
    int flag = 0;
    for(int i = 0 ; i < n - m + 1 ; i++)
        if(hash[i] - multiplier*hash[i+m] == phv)
        {
            flag = 1;
            break;
        }
    if(flag)
        printf("YES\n");
    else
        printf("NO\n");
}
int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        int n;
        scanf("%d",&n);
        int arr[n+9];
        for(int i=0 ; i < n ; i++)
            scanf("%d",&arr[i]);
        char str[n+9];
        for(int i = 1 ; i < n ; i++)
            if(arr[i] == arr[i-1])
                str[i-1] = 'E';
            else if(arr[i] > arr[i-1])
                str[i-1] = 'G';
            else
                str[i-1] = 'L';
        n--;
        char pattern[n+9];
        scanf("%s",pattern);
        int m = strlen(pattern);
        solve(str , pattern , n , m);
    }
    return 0;
}