268. Missing Number java solutions

Given an array containing n distinct numbers taken from 0, 1, 2, ..., n, find the one that is missing from the array.

For example,
Given nums = [0, 1, 3] return 2.

Note:
Your algorithm should run in linear runtime complexity. Could you implement it using only constant extra space complexity?

Credits:
Special thanks to @jianchao.li.fighter for adding this problem and creating all test cases.

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

异或 两次，即可得最后缺少的元素。