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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c++ code:
class Solution {
public:
int missingNumber(vector<int>& nums) {
int ret=0;
for(int i=0;i<nums.size();i++)
ret ^= (i+1) ^ nums[i];
return ret;
}
};原文：http://blog.csdn.net/itismelzp/article/details/51377969