Count the Number of Beautiful Subarrays — LeetCode 2588 Python Solution
MediumBit ManipulationArrayHash TablePrefix Sum
- Problem
- #2588
- Pattern
- Prefix Sum
- Reading time
- 2 min
- Source
- leetcode.com
The problem
You are given a 0-indexed integer array nums. In one operation, you can: Choose two different indices i and j such that 0 <= i, j < nums.length.
Example
- Input
- nums = [4,3,1,2,4]
- Output
- 2
- Explanation
- There are 2 beautiful subarrays in nums: [4,3,1,2,4] and [4,3,1,2,4].
Python solution
Python
class Solution:
def beautifulSubarrays(self, nums: List[int]) -> int:
cnt = Counter({0: 1})
ans = mask = 0
for x in nums:
mask ^= x
ans += cnt[mask]
cnt[mask] += 1
return ansComplexity
| Measure | Complexity |
|---|---|
| Time | O(n) |
| Space | O(n) auxiliary |
Pattern: Prefix Sum
Precompute running totals once so any range query becomes a single subtraction. LeetCode 2588. Count the Number of Beautiful Subarrays is filed here because LeetCode tags it Prefix Sum, which is the vocabulary this hub collects.
The prefix sum guide has the Python template for the pattern and the 157 LeetCode problems that use it.
Related problems
Frequently asked questions
- How hard is LeetCode 2588. Count the Number of Beautiful Subarrays?
- LeetCode 2588. Count the Number of Beautiful Subarrays is rated Medium on LeetCode.
- What is the time complexity of LeetCode 2588. Count the Number of Beautiful Subarrays?
- The Python solution on this page runs in O(n).
- What is the space complexity of LeetCode 2588. Count the Number of Beautiful Subarrays?
- The Python solution on this page uses O(n) auxiliary space.
- What topics does LeetCode 2588. Count the Number of Beautiful Subarrays cover?
- LeetCode 2588. Count the Number of Beautiful Subarrays is tagged Bit Manipulation, Array, Hash Table and Prefix Sum on LeetCode.