136. Single Number I

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?

Related Issue Single Number II Single Number III

// Xor operation
public class Solution {
    public int singleNumber(int[] nums) {
        int res = 0;
        for(int v : nums){
            res ^= v;
        }
        return res;
    }
}