In this post, we are going to solve the 136. Single Number problem of Leetcode. This problem 136. Single Number is a Leetcode easy level problem. Let’s see the code, 136. Single Number – Leetcode Solution.

Problem

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

You must implement a solution with a linear runtime complexity and use only constant extra space.

Example 1 :

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

Example 2 :

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

Example 3 :

Input: nums = [1]
Output: 1

Constraints

• 1 <= nums.length <= 3 * 104
• -3 * 104 <= nums[i] <= 3 * 104
• Each element in the array appears twice except for one element which appears only once.

Now, let’s see the code of 136. Single Number – Leetcode Solution.

Single Number – Leetcode Solution

136. Single Number – Solution in Java

class Solution {
    public int singleNumber(int[] nums) {
        int xor = nums[0];
        for(int i=1;i<nums.length;i++){
            xor^=nums[i];
        }
        return xor;
    }
}

136. Single Number – Solution in C++

class Solution {
public:
    int singleNumber(vector<int>& nums) { 
       int ans=0;
	   for(auto x:nums)
	   ans^=x;
	   return ans;
    }
};

136. Single Number – Solution in Python

class Solution:
    def singleNumber(self, nums: List[int]) -> int:
        xor = 0
        for num in nums:
            xor ^= num
        
        return xor

Note: This problem 136. Single Number is generated by Leetcode but the solution is provided by CodingBroz. This tutorial is only for Educational and Learning purpose.