Fibonacci.Numbers(Pair)

/*Author Arpit Singh Verma*/
/*Recursive Approach of Fibonacci Numbers*/
/*Most important Fibonacci Numbers Imp for Cp*/
/*Cp-algorithms*/
#include"bits/stdc++.h"
using namespace std;  
int main(){
      
        
        //main code of the problem
        //creating a pair of int And INT 
        pair<int,int> fib(int n){
              
               if(n==0)
                 
                 return {0,1};

                 auto p =  fib(n >> 1);
                 int c  = p.first * (2 * p.second * p.second);
                 int d = p.first * p.first + p.second * p.second;

                 if(n&1)

                 return {d,c+d};
                 else 
                 return {c,d};
//the above code returns Fn and Fn+1 as a pair.
        }
}
      
        /*Contains main code to be implemented*/
       
        //Anything in the number raise to power --->>>0<<<<--- is 1 so Here power is b and b == 0  therefore a = 1;

     


        //DIVING B BY 2  and then performing the actions

        /*----------->>>>>Jai Bhole <<<<<<<--------------*/