# C++ code to find minimum operations to make numbers c and d

Suppose we have two numbers c and d. Amal has two numbers a and b initially both are zero. Amal wants to perform some operation on them. Before performing each operation, some positive integer k is picked, which is then used to perform one of the following operations −

• add number k to both a and b, or

• add number k to a and subtract k from b, or

• add number k to b and subtract k from a.

We have to find the minimum number of operations needed to make a and b equal to c and d respectively. If not possible, return -1.

So, if the input is like c = 3; d = 5, then the output will be 2, because for k = 1, we get the numbers (1, 1), for k = 8, the pair can be (-7, 9), for k = 7, it can be (0, 2) and for k = 3, it can be (3, 5)

## Steps

To solve this, we will follow these steps −

if (c ^ d) is odd, then:
return -1
otherwise when c is same as 0 and d is same as 0, then:
return 0
otherwise when c is same as d, then:
return 1
Otherwise
return 2

## Example

Let us see the following implementation to get better understanding −

#include <bits/stdc++.h>
using namespace std;
int solve(int c, int d){
if ((c ^ d) & 1)
return -1;
else if (c == 0 && d == 0)
return 0;
else if (c == d)
return 1;
else
return 2;
}
int main(){
int c = 3;
int d = 5;
cout << solve(c, d) << endl;
}

## Input

3, 5

## Output

2

Updated on: 11-Mar-2022

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