Help me in solving ABCXOR problem

help
,
1

My issue

Can someone Please help me with this Question

My code

#include <iostream>
using namespace std;

int main() {
	// your code goes here
	return 0;
}

Problem Link: ABCXOR Problem - CodeChef

2

@checking123
Plzz refer my solution

#include <iostream>
using namespace std;

int main() {
	// your code goes here
	int t;
	cin>>t;
	while(t--)
	{
	    long long int n,k;
	    cin>>n>>k;
	    long long int p=1;
	    while(n--)
	    {
	        p=p*2;
	    }
	   long long int ans=(p-1)*(p-2);
	   cout<<ans<<endl;
	}
	return 0;
}
3

I just want to Know the detailed approach how you think that and what is the logic behind this
Please can you explain that.

4

@checking123

Its totally maths
first how many choices u have is :- 
let m=2^n;
the choices we have is mc3*3!
3! is to rearrange a,b,c.
but this includes repetition.
so we divide it my m.
which will gives us the formula (mc3*3!)/m;
and by some smaller cases observation u will find that this formula is independent of k.
. So solve this formula u will get the actual formula which is (m-1)*(m-2).

Its quite less intuitive but yeah easy to get it from observation .

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