**LeetCode Problem | LeetCode Problems For Beginners | LeetCode Problems & Solutions | Improve Problem Solving Skills | LeetCode Problems Java | LeetCode Solutions in C++**

Hello **Programmers/Coders,** Today we are going to share ** solutions to the Programming problems of LeetCode Solutions in C++, Java, & Python**. At Each Problem with Successful submission with

**all Test Cases Passed,**you will get a score or marks and LeetCode Coins. And after solving maximum problems, you will be getting stars. This will highlight your profile to the recruiters.

In this post, you will find the solution for the **Single Number** **in C++, Java & Python-LeetCode problem**. We are providing the **correct and tested solutions** to coding problems present on **LeetCode**. If you are not able to solve any problem, then you can take help from our Blog/website.

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**About LeetCode**

*LeetCode* is one of the most well-known online judge platforms to help you enhance your skills, expand your knowledge and prepare for technical interviews.

LeetCode is for **software engineers who are looking to practice technical questions and advance their skills**. Mastering the questions in each level on LeetCode is a good way to prepare for technical interviews and keep your skills sharp. They also have a repository of solutions with the reasoning behind each step.

LeetCode has over 1,900 questions for you to practice, covering many different programming concepts. Every coding problem has a classification of either *Easy*, *Medium*, or *Hard*.

**LeetCode problems focus on algorithms and data structures. Here is some topic you can find problems on LeetCode:**

- Mathematics/Basic Logical Based Questions
- Arrays
- Strings
- Hash Table
- Dynamic Programming
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- Trees & Graphs
- Greedy Algorithms
- Breadth-First Search
- Depth-First Search
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- BST (Binary Search Tree)
- Database
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- Recursion, etc.

Leetcode has a huge number of test cases and questions from interviews too like Google, Amazon, Microsoft, Facebook, Adobe, Oracle, Linkedin, Goldman Sachs, etc. LeetCode helps you in getting a job in Top MNCs. To crack FAANG Companies, LeetCode problems can help you in building your logic.

** Link for the Problem** –

**Single Number– LeetCode Problem**

Single Number– LeetCode Problem

**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 * 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.

Single Number– LeetCode Solutions

Single Number Solution in C++:

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

Single Number Solution in Java:

class Solution { public int singleNumber(int[] nums) { int ans = 0; for (final int num : nums) ans ^= num; return ans; } }

Single Number Solution in Python:

class Solution: def singleNumber(self, nums: List[int]) -> int: return reduce(lambda x, y: x ^ y, nums, 0)