LC-2588 Medium LeetCode

2588. Count the Number of Beautiful Subarrays

Array Hash Table Bit Manipulation Prefix Sum

Read the full problem statement on LeetCode.

Difficulty: medium Acceptance: 52% Topics: Array, Hash Table, Bit Manipulation, Prefix Sum

Reading material

Arrays & Hashing 12 min Bit Manipulation 10 min Prefix Sums & Difference Arrays 11 min

Reference solution (spoiler · python)

# Time:  O(n)
# Space: O(n)

import collections


# freq table, combinatorics
class Solution(object):
    def beautifulSubarrays(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        cnt = collections.Counter()
        cnt[0] = 1
        result = curr = 0
        for x in nums:
            curr ^= x
            result += cnt[curr]
            cnt[curr] += 1
        return result

Solution from kamyu104/LeetCode-Solutions · MIT