FIBOSUM problem

#1

https://hack.codingblocks.com/contests/c/473/758
getting the correct answer while running, but wrong answer while submitting. Please help.

#2

I think you wanted to paste the link to your code

#3

import java.util.; import java.lang.Math.;
public class Main {
static void multiply(long a[][],long b[][])
{
long mul[][]= new long[3][3];
for(int i=0;i<3;i++)
{
for(int j=0;j<3;j++)
{
mul[i][j]= 0;
for(int k=0;k<3;k++)
mul[i][j]+= a[i][k]*b[k][j];
}
}
for(int i=0;i<3;i++)
for(int j=0;j<3;j++)
a[i][j]= mul[i][j];
}

static long fib(long m[][],int n)
{
   long nt[][]={{1,0,0},{1,0,1},{1,1,1}};
   if(n==1)
   return m[0][0]+m[2][0];
    fib(m,n/2);
    multiply(m,m);
   if(n%2!=0)
   multiply(m,nt);
    return m[0][0]+m[2][0];
    
}
public static void main(String args[]) {
  Scanner sc= new Scanner(System.in);
  int T= sc.nextInt();
  for(int i=0;i<T;i++)
  {
      long m[][]={{1,0,0},{1,0,1},{1,1,1}};
      long M= sc.nextLong(); long N= sc.nextLong();int a=(int)M-2; int b=(int)N-1;long at,bt;
       if(M==0) at=0;
     else if(M-1==0){at=0;} else if(M-1==1){at=1;}
      else
       at= fib(m,a); 
       long u[][]={{1,0,0},{1,0,1},{1,1,1}};
        if(N==0){bt=0;} else if(N==1){bt=1;}
      else{
     //System.out.println("calling");
       bt= fib(u,b);}
     // System.out.println(at+" "+bt);
     //  System.out.println(M+" "+N+" "+a+" "+b);
      long ans= (bt-at)%((long)(Math.pow(10,9)+7));
      System.out.println(ans);
  }
}

}

#4

Have a look at this first