[Leetcode] 136. Single Number

Description

Given a non-empty array of integers, every element appears twice except for one. Find that single one.

Note:

Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory?

Example 1:

Input: [2,2,1]
Output: 1

Example 2:

Input: [4,1,2,1,2]
Output: 4

Program:

class Solution {
    public int singleNumber(int[] nums) {
       int result = 0;
       for (int i = 0; i < nums.length; i++) {
           result ^= nums[i];
       }
        return result;
    }
}

该方法实际使用了异或运算即为xor

T T = T

T F = T

F T = T

F F = F

e.g.:

((2^2)^(1^1)^(4^4)^(5)) => (0^0^0^5) => 5.