[leetcode]286. 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?

比较简单的一道题

下面给出了两种方法：

public int missingNumber(int[] nums) {
        int[] count=new int[nums.length+1];
        for(int i=0;i

第二种是位运算，使用了位异或的特点，即0^x=x  x^x=0

    public int missingNumber(int[] nums) {
        int res=0;
        for(int i=0;i