Leetcode 371 Sum of Two Integers

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1. 1. Leetcode 371 Sum of Two Integers

Leetcode 371 Sum of Two Integers

Calculate the sum of two integers a and b, but you are not allowed to use the operator + and -.

Example:

Given a = 1 and b = 2, return 3.

题目要求不能使用+和-，就可以想到是用位运算解决

• ^ 异或，相当于无进位的加法，即俩个位置不一样即为1，否则为0
• & 与，求进位，进位的产生是俩个位置上都是1，即1&1=1
• << 由于是进位，还得将其向左移一位，
• 直到a==0时，返回b即可

func getSum(a int, b int) int {
	for a != 0 {
		a, b = (a&b)<<1, a^b
	}
	return b
}