260. Single Number III

Medium (Trung bình) Python 🔗 Xem trên LeetCode

📋 Đề Bài

Given an integer array nums, in which exactly two elements appear only once and all the other elements appear exactly twice. Find the two elements that appear only once. You can return the answer in any order.

You must write an algorithm that runs in linear runtime complexity and uses only constant extra space.

 

Example 1:

Input: nums = [1,2,1,3,2,5]
Output: [3,5]
Explanation:  [5, 3] is also a valid answer.

Example 2:

Input: nums = [-1,0]
Output: [-1,0]

Example 3:

Input: nums = [0,1]
Output: [1,0]

 

Constraints:

  • 2 <= nums.length <= 3 * 104
  • -231 <= nums[i] <= 231 - 1
  • Each integer in nums will appear twice, only two integers will appear once.

🧠 Thuật Toán & Kỹ Thuật

Bit Manipulation (Thao tác bit)
⏱️ Thời gian O(n²)
💾 Không gian O(n)

💻 Lời Giải

Python 0260-single-number-iii.py 
class Solution:
    def singleNumber(self, nums: List[int]) -> List[int]:
        res = 0
        
        for num in nums:
            res ^= num
            
        bitAt = -1
        
        for i in range(31, -1, -1):
            if (res >> i) & 1:
                bitAt = i
                break
            
        x = 0
        for num in nums:
            if (num >> bitAt) & 1:
                x ^= num
        
        return [x, res^x]