LeetCode 30 day Challenge #1 : Single Number

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:

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

Example 2:

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

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C++

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class Solution {

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public:

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    int singleNumber(vector<int>& nums) {

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        int result = 0;

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        for(int n : nums)

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            result ^= n;

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        return result;

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    }

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};