# Fair Candy Swap in Python

PythonServer Side ProgrammingProgramming

Suppose A and B are two friends. They have candy bars of different sizes. Here A[i] is the size of the i-th bar of candy owned by A, and B[j] is the size of the j-th bar of candy owned by B.

Since they are friends, they want to exchange one candy bar each so that after the exchange, both A and B have the same total amount of candy. (The total amount of candy a person has is the sum of the sizes of candy bars they have.) We have to return an integer array suppose ans, where ans is the size of the candy bar that A must exchange, and ans is the size of the candy bar that B must exchange. If there are multiple answers, we will return only one of them.

For example, if A = [1, 2] and B = [2, 3], then output will be [1, 2]

To solve this, we will follow these steps −

• Take the difference between the sum of A and sum of B, then divide it by 2, and take the integer part into diff
• convert B into a set
• for i in A
• if i – diff in B, then return [i, i – diff]

## Example

Let us see the following implementation to get better understanding −

Live Demo

class Solution(object):
def fairCandySwap(self, A, B):
diff = (sum(A) - sum(B))//2
B=set(B)
for i in A:
if i- diff in B:
return [i,i-diff]
ob1 = Solution()
print(ob1.fairCandySwap([1,2], [2,3]))

## Input

[1,2]
[2,3]

## Output

[1,2]