136.single-number

Statement

简体中文English

Metadata

• Link: 只出现一次的数字
• Difficulty: Easy
• Tag: 位运算 数组

给定一个非空整数数组，除了某个元素只出现一次以外，其余每个元素均出现两次。找出那个只出现了一次的元素。

说明：

你的算法应该具有线性时间复杂度。 你可以不使用额外空间来实现吗？

示例 1:

输入: [2,2,1]
输出: 1

示例 2:

输入: [4,1,2,1,2]
输出: 4

Metadata

• Link: Single Number
• Difficulty: Easy
• Tag: Bit Manipulation Array

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.

Solution

Python 3

from typing import List


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

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最后更新: October 11, 2023