LC-2063 Medium LeetCode

2063. Vowels of All Substrings

Math String Dynamic Programming Combinatorics

Read the full problem statement on LeetCode.

Difficulty: medium Acceptance: 55% Topics: Math, String, Dynamic Programming, Combinatorics

Reading material

Math & Geometry 12 min Strings 12 min 1-D Dynamic Programming 16 min

Reference solution (spoiler · python)

# Time:  O(n)
# Space: O(1)

class Solution(object):
    def countVowels(self, word):
        """
        :type word: str
        :rtype: int
        """
        VOWELS = set("aeiou")
        return sum((i-0+1) * ((len(word)-1)-i+1) for i, c in enumerate(word) if c in VOWELS)

Solution from kamyu104/LeetCode-Solutions · MIT