Algorithm
Problem Name: 888. Fair Candy Swap
Alice and Bob have a different total number of candies. You are given two integer arrays aliceSizes and bobSizes where aliceSizes[i] is the number of candies of the ith box of candy that Alice has and bobSizes[j] is the number of candies of the jth box of candy that Bob has.
Since they are friends, they would like to exchange one candy box each so that after the exchange, they both have the same total amount of candy. The total amount of candy a person has is the sum of the number of candies in each box they have.
Return an integer array answer where answer[0] is the number of candies in the box that Alice must exchange, and answer[1] is the number of candies in the box that Bob must exchange. If there are multiple answers, you may return any one of them. It is guaranteed that at least one answer exists.
Example 1:
Input: aliceSizes = [1,1], bobSizes = [2,2] Output: [1,2]
Example 2:
Input: aliceSizes = [1,2], bobSizes = [2,3] Output: [1,2]
Example 3:
Input: aliceSizes = [2], bobSizes = [1,3] Output: [2,3]
Constraints:
1 <= aliceSizes.length, bobSizes.length <= 1041 <= aliceSizes[i], bobSizes[j] <= 105- Alice and Bob have a different total number of candies.
- There will be at least one valid answer for the given input.
Code Examples
#1 Code Example with C++ Programming
Code -
C++ Programming
class Solution {
public:
vector<int> fairCandySwap(vector<int>& A, vector<int>& B) {
int sumA(0), sumB(0), half;
unordered_set < int>s;
for(auto& x: A) sumA += x;
for(auto& x: B) sumB += x, s.insert(x);
half = (sumA + sumB) / 2;
for(auto& x: A) if(s.count(half - (sumA - x))) return {x, half - (sumA - x)};
}
};
Input
Output
#2 Code Example with Java Programming
Code -
Java Programming
class Solution {
public int[] fairCandySwap(int[] A, int[] B) {
int sumA = 0;
int sumB = 0;
Set < Integer> set = new HashSet<>();
for (int num : A) {
sumA += num;
set.add(num);
}
for (int num : B) {
sumB += num;
}
int diff = (sumA - sumB)/2;
int[] ans = new int[2];
for (int num : B) {
if (set.contains(num + diff)) {
ans[0] = num + diff;
ans[1] = num;
break;
}
}
return ans;
}
}
Input
Output
#3 Code Example with Javascript Programming
Code -
Javascript Programming
const fairCandySwap = function(aliceSizes, bobSizes) {
let sum = 0
for(let e of aliceSizes) sum += e
for(let e of bobSizes) sum -= e
// sum > 0, alice > bob
// sum < 0, alice < bob
sum /= 2
const set = new Set()
for(let e of aliceSizes) set.add(e)
for(let e of bobSizes) {
if(set.has(e + sum)) return [e + sum, e]
}
return [0]
};
Input
Output
#4 Code Example with Python Programming
Code -
Python Programming
class Solution:
def fairCandySwap(self, A, B):
"""
:type A: List[int]
:type B: List[int]
:rtype: List[int]
"""
a, b = set(A), set(B)
diff =(sum(A) - sum(B)) // 2
for c in B:
if c + diff in a:
return [c + diff, c]
Input
Output
#5 Code Example with C# Programming
Code -
C# Programming
using System.Collections.Generic;
using System.Linq;
namespace LeetCode
{
public class _0888_FairCandySwap
{
public int[] FairCandySwap(int[] A, int[] B)
{
var different = (B.Sum() - A.Sum()) / 2;
var set = new HashSet < int>(B);
foreach (var num in A)
{
if (set.Contains(num + different))
return new int[] { num, num + different };
}
return null;
}
}
}
Input
Output