light Online Judge 1006

Problem Link : http://lightoj.com/volume_showproblem.php?problem=1006

      The concept is just like Fibonacci series except that it has six terms. Convert the recursion method into iterative method and it will work. Now the problem lies with the overflow.
 
     The first 6 numbers are given . You have to find nth term of this series . Simple a loop is enough for this .      

      Use Modular arithmatic for intermdeiate calculation . The modular arithmetic says
                   i) (A + B ) % M = ( (A% M) + (B % M) ) % M.
                   ii) (A x B ) % M = ( (A% M) x (B % M) ) % M.
                

    Use long long int for data type . Hope it helps

Code :
 #include<iostream>
#include<cstdio>
using namespace std;

int main() {
    long long int a,i,fn[10001],n,j, cases;
    cin>>cases;

    for(j=1;j<=cases;j++){
        cin>>a>>b>>c>>d>>e>>f>>n;

        fn[0]= a ;
        fn[1]= b ;
        fn[2]= c ;
        fn[3]= d ;
        fn[4]= e ;
        fn[5]= f ;

        for(i=6;i<=n;i++)
                fn[i]=( fn[i-1] + fn[i-2] + fn[i-3] + fn[i-4] + fn[i-5] + fn[i-6] )  % 10000007 ;

        printf("Case %lld: ", j);
        cout<<fn[n]% 10000007<<endl;
    }
    return 0;
}