package main

func singleNumber(nums []int) int {
	imap := make(map[int]int)
	for _ ,v := range nums {
		imap[v] ++
	}
	for k ,v := range imap {
		if v == 1 {
			return k
		}
	}
	return -1
}

// 还有一种位运算的方法

func singleNumber1(nums []int) (res int) {
	for i := 0 ; i < 32 ; i ++ {
		posSum := 0
		for _ ,v := range nums {
			posSum += (v >> i) & 1
		}
		if posSum % 3 == 1 {
			res |= 1 << i
		}
	}
	res = int(int32(res))
	return
}

func main() {

}