2586. Count the Number of Vowel Strings in Range
EasyLeetCodeAYou are given a 0-indexed array of string words and two integers left and right.
A string is called a vowel string if it starts with a vowel character and ends with a vowel character where vowel characters are 'a', 'e', 'i', 'o', and 'u'.
Return the number of vowel strings words[i] where i belongs to the inclusive range [left, right].
Example 1:
Input: words = ["are","amy","u"], left = 0, right = 2
Output: 2
Explanation:
- "are" is a vowel string because it starts with 'a' and ends with 'e'.
- "amy" is not a vowel string because it does not end with a vowel.
- "u" is a vowel string because it starts with 'u' and ends with 'u'. The number of vowel strings in the mentioned range is 2.
Example 2:
Input: words = ["hey","aeo","mu","ooo","artro"], left = 1, right = 4
Output: 3
Explanation:
- "aeo" is a vowel string because it starts with 'a' and ends with 'o'.
- "mu" is not a vowel string because it does not start with a vowel.
- "ooo" is a vowel string because it starts with 'o' and ends with 'o'.
- "artro" is a vowel string because it starts with 'a' and ends with 'o'. The number of vowel strings in the mentioned range is 3.
Constraints:
1 <= words.length <= 1000
1 <= words[i].length <= 10
words[i]
consists of only lowercase English letters0 <= left <= right < words.length
How to solve the problem
- Using
words[i][0]
andwords[i][-1]
to get the first and last character.
Code
Python
class Solution:
def vowelStrings(self, words: List[str], left: int, right: int) -> int:
vowel = {'a', 'e', 'i', 'o', 'u'}
counter = 0
for i in range(left, right + 1):
if words[i][0] in vowel and words[i][-1] in vowel:
counter += 1
return counter
Complexity
Time complexity: O(n)
- One loop.
Space complexity: O(1)
- No extra space
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