Single Number Problem


Description

LeetCode Problem 136.

Given a non-emptyarray of integers nums, every element appears twice except for one. Find that single one.

You mustimplement a solution with a linear runtime complexity and useonly constantextra space.

Example 1:

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

Example 2:

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

Example 3:

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Input: nums = [1]
Output: 1

Constraints:

  • 1 <= nums.length <= 3 * 10^4
  • -3 * 10^4 <= nums[i] <= 3 * 10^4
  • Each element in the array appears twice except for one element which appears only once.


Sample C++ Code

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class Solution {
public:
    int singleNumber(vector<int>& nums) {
        int n = 0;
        for (int i = 0; i < nums.size(); i ++) {
            n = n ^ (nums[i]);
        }    
        return n;
    }
};




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