Matrix exponentiation used in many areas - For finding recurrences, fibonocci sum, etc

MatrixExponentiation.java

/*
  Can be used for bigger powers but be careful of long value overflow
  current[][] - is the initial state of the matrix used 
  result[][] - is the final matrix after exponentiation
  power - in the argument tells the exponent of the matrix
  choose mod accordingly !
*/

public class MatrixExponentiation{

  public static long[][] mult(long[][] A,long[][] B){
        long[][] C = new long[3][3];
        
        for(int i = 0; i <3; i++){
            for(int j = 0; j < 3; j++) {                
                long tmp=0L;
                for(int k = 0; k < 3; k++) {
                    tmp += A[i][k]*B[k][j];
                }                
               C[i][j]= tmp%mod;
            }
        }
        return C;        
    }
    
    public static long[][] getM(long power){
        long[][] result = {{1,0,0},{0,1,0},{0,0,1}};
        
        long[][] current = {{0,0,3},{1,0,2},{0,1,1}};
                
        while(power>0){
            if(power%2==1){                
                result = mult(result,current);   
            }              
            current = mult(current,current);
            power = power/2;            
        }        
        return result;
        
    }

}