From db4615b3063ec4d704e9b5911c87e0664bb9ec15 Mon Sep 17 00:00:00 2001
From: Antim Pal <134076504+iamAntimPal@users.noreply.github.com>
Date: Tue, 15 Apr 2025 06:58:55 +0530
Subject: [PATCH 1/4] Create 136. Single Number.py
Co-Authored-By: Antim-IWP <203163676+Antim-IWP@users.noreply.github.com>
Co-Authored-By: Shiwangi Srivastava <174641070+IamShiwangi@users.noreply.github.com>
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Solution/136. Single Number/136. Single Number.py | 0
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From 1a88ccfeb4c264bdd61373257d865d9c92588e07 Mon Sep 17 00:00:00 2001
From: Antim Pal <134076504+iamAntimPal@users.noreply.github.com>
Date: Tue, 15 Apr 2025 06:59:16 +0530
Subject: [PATCH 2/4] Update 136. Single Number.py
Co-Authored-By: Antim-IWP <203163676+Antim-IWP@users.noreply.github.com>
Co-Authored-By: Shiwangi Srivastava <174641070+IamShiwangi@users.noreply.github.com>
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Solution/136. Single Number/136. Single Number.py | 3 +++
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+class Solution:
+ def singleNumber(self, nums: list[int]) -> int:
+ return functools.reduce(operator.xor, nums, 0)
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From ab5afd91e90c9df66ea8cf914da7fa6ef5df71f0 Mon Sep 17 00:00:00 2001
From: Antim Pal <134076504+iamAntimPal@users.noreply.github.com>
Date: Tue, 15 Apr 2025 06:59:28 +0530
Subject: [PATCH 3/4] Create readme.md
Co-Authored-By: Antim-IWP <203163676+Antim-IWP@users.noreply.github.com>
Co-Authored-By: Shiwangi Srivastava <174641070+IamShiwangi@users.noreply.github.com>
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Solution/136. Single Number/readme.md | 0
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From b9468d474bf6ca12d9486e1d9106300f62de50c2 Mon Sep 17 00:00:00 2001
From: Antim Pal <134076504+iamAntimPal@users.noreply.github.com>
Date: Tue, 15 Apr 2025 07:01:06 +0530
Subject: [PATCH 4/4] Update readme.md
Co-Authored-By: Antim-IWP <203163676+Antim-IWP@users.noreply.github.com>
Co-Authored-By: Shiwangi Srivastava <174641070+IamShiwangi@users.noreply.github.com>
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Solution/136. Single Number/readme.md | 119 ++++++++++++++++++++++++++
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+---
+comments: true
+difficulty: Easy
+edit_url: https://github.com/doocs/leetcode/edit/main/solution/0100-0199/0136.Single%20Number/README_EN.md
+tags:
+ - Bit Manipulation
+ - Array
+---
+
+
+
+# [136. Single Number](https://leetcode.com/problems/single-number)
+
+[中文文档](/solution/0100-0199/0136.Single%20Number/README.md)
+
+## Description
+
+
+
+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.
+
+
+
+
+## Solutions
+
+
+
+### Solution 1: Bitwise Operation
+
+The XOR operation has the following properties:
+
+- Any number XOR 0 is still the original number, i.e., $x \oplus 0 = x$;
+- Any number XOR itself is 0, i.e., $x \oplus x = 0$;
+
+Performing XOR operation on all elements in the array will result in the number that only appears once.
+
+The time complexity is $O(n)$, where $n$ is the length of the array. The space complexity is $O(1)$.
+
+
+
+#### Python3
+
+```python
+class Solution:
+ def singleNumber(self, nums: List[int]) -> int:
+ return reduce(xor, nums)
+```
+
+#### Java
+
+```java
+class Solution {
+ public int singleNumber(int[] nums) {
+ int ans = 0;
+ for (int v : nums) {
+ ans ^= v;
+ }
+ return ans;
+ }
+}
+```
+
+#### C++
+
+```cpp
+class Solution {
+public:
+ int singleNumber(vector& nums) {
+ int ans = 0;
+ for (int v : nums) {
+ ans ^= v;
+ }
+ return ans;
+ }
+};
+```
+
+
+
+
+
+
+
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