[leetcode] 136. Single Number

Given an 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?

第一想法是用HashMap<Integer, Boolean>，用 异或 更简单

一刷：

    public int singleNumber(int[] nums) {
        int result = nums[0];
        for (int i = 1; i <nums.length; i++) {
            result^=nums[i];
        }
        return result;
    }