fair-candy-swap (https://leetcode.com/problems/fair-candy-swap/description/)

accepted.go

package main

import (
	"fmt"
	"sort"
)

func main() {
	A := []int{32, 38, 8, 1, 9}
	B := []int{68, 92}
	fmt.Println(fairCandySwap(A, B))
	// fairCandySwap(A, B)
}

func fairCandySwap(A []int, B []int) []int {
	sumA := 0
	sumB := 0
	for _, c := range A {
		sumA += c
	}

	for _, c := range B {
		sumB += c
	}

	sort.Ints(A)
	sort.Ints(B)

	i := 0
	j := 0

	diff := sumA - sumB

	for i < len(A) && j < len(B) {
		if A[i]-B[j] == diff/2 {
			return []int{A[i], B[j]}
		}
		if diff > 0 {
			if A[i]-B[j] < diff/2 {
				i++
			} else {
				j++
			}
		} else {
			if A[i]-B[j] > diff/2 {
				j++
			} else {
				i++
			}
		}
	}
	return []int{}
}

main.go

package main

import (
	"fmt"
)

func main() {
	A := []int{32, 38, 8, 1, 9}
	B := []int{68, 92}
	fmt.Println(fairCandySwap(A, B))
	// fairCandySwap(A, B)
}

func fairCandySwap(A []int, B []int) []int {
	sumA, sumB := 0, 0

	inA := map[int]struct{}{}
	for _, a := range A {
		sumA += a
		inA[a] = struct{}{}
	}
	for _, b := range B {
		sumB += b
	}

	m := (sumA - sumB) / 2
	a, b := 0, 0
	for _, b := range B {
		a = b + m
		if _, ok := inA[a]; ok {
			break
		}
	}
	return []int{a, b}
}