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LeetCode Top 100 Liked Questions 136. Single Number (Java版; Easy)

题目描述

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

第一次做; a^a==0

/*
异或
*/
class Solution {
    public int singleNumber(int[] nums) {
        //problem ensures a non-empty array
        int res = 0;
        for(int num : nums)
            res ^= num;
        return res;
    }
}