LeetCode 136. Single Number

136. Single Number

Difficulty: Easy

Given a non-empty 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?

Example 1:

1 2	Input: [2,2,1] Output: 1

Example 2:

1 2	Input: [4,1,2,1,2] Output: 4

Solution

Language: Java

class Solution {
    public int singleNumber(int[] nums) {
        if (nums == null || nums.length % 2 == 0) {
            return -1;
        }
        int result = 0;
        for (int n : nums) {
            result ^= n;
        }
        return result;
    }
}