[LeetCode 268] Missing Number

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?

solution:

1. XOR from 1 to n

2. use that result XOR each element in array, to find different one.

XOR can used to store different information between two things

public int missingNumber(int[] nums) {
        int sum = 0;
        int len = nums.length;
        while(len>0) {
            sum = sum^len;
            len--;
        }
        for(int i=0;i<nums.length;i++){
            sum = sum^nums[i];
        }
        return sum;
    }