Count Vowels in a String

Solved

Difficulty: Basic Accuracy: — Submissions: 0 Points: 1

Given a string s made of English letters, count how many of its characters are vowels. Both lowercase and uppercase a, e, i, o, u count.

Examples:

Input: s = "programming"

Output: 3

Explanation: The vowels are o, a and i.

Input: s = "Rhythm"

Output: 0

Explanation: There is no vowel in the word.

Constraints:

1 ≤ s.length ≤ 10^5
s contains only English letters

Expected Complexities

Time Complexity: O(n) Auxiliary Space: O(1)

Company Tags

Wipro

Topic Tags

Basic Strings

Go through the string once and increase a counter whenever the current character, lowered to lowercase, is one of a, e, i, o, u. Putting the vowels in a small set or string makes the membership test a one-liner.

class Solution:
    def countVowels(self, s):
        return sum(1 for ch in s.lower() if ch in 'aeiou')