Problem:
Score : 100 points

Problem Statement

We have an N \times N square grid.

We will paint each square in the grid either black or white.

If we paint exactly A squares white, how many squares will be painted black?

Constraints

1 \leq N \leq 100

0 \leq A \leq N^2

Inputs

Input is given from Standard Input in the following format:

N
A

Outputs

Print the number of squares that will be painted black.

Sample Input 1

3
4

Sample Output 1

5

There are nine squares in a 3 \times 3 square grid.
Four of them will be painted white, so the remaining five squares will be painted black.

Sample Input 2

19
100

Sample Output 2

261

Sample Input 3

10
0

Sample Output 3

100

As zero squares will be painted white, all the squares will be painted black.

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <bits/stdc++.h>
using namespace std;

int main() {
	int N, k;
	cin >> N >> k;
  
  	int l = 0;
  	for (int i=0; i < N; i++) {
    	int x;
      	cin >> x;
      	
      	int a, b;
      	a = 2*x;
      
      	if(k > x) {
        	b = 2*(x-k);
          	if (b > a) {
            	l += a;
            }
          	else if(a >= b) {
            	l += b;
            }
        }
      	else if(x >= k) {
        	b = 2*(k-x);
          	l += b;
        }
    }
  
  	cout << l << endl;
}