# Single Number – Leetcode Solution

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.