2063-vowels-of-all-substrings.adoc

2063. Vowels of All Substrings

{leetcode}/problems/vowels-of-all-substrings/[LeetCode - 2063. Vowels of All Substrings ^]

Given a string word, return the sum of the number of vowels (’a'`, 'e'`, ’i'`, ’o'`, and ’u'`) _in every substring of _`word.

A substring is a contiguous (non-empty) sequence of characters within a string.

Note: Due to the large constraints, the answer may not fit in a signed 32-bit integer. Please be careful during the calculations.

Example 1:

Input: word = "aba"
Output: 6
Explanation:
All possible substrings are: "a", "ab", "aba", "b", "ba", and "a".
- "b" has 0 vowels in it
- "a", "ab", "ba", and "a" have 1 vowel each
- "aba" has 2 vowels in it
Hence, the total sum of vowels = 0 + 1 + 1 + 1 + 1 + 2 = 6.

Example 2:

Input: word = "abc"
Output: 3
Explanation:
All possible substrings are: "a", "ab", "abc", "b", "bc", and "c".
- "a", "ab", and "abc" have 1 vowel each
- "b", "bc", and "c" have 0 vowels each
Hence, the total sum of vowels = 1 + 1 + 1 + 0 + 0 + 0 = 3.

Example 3:

Input: word = "ltcd"
Output: 0
Explanation: There are no vowels in any substring of "ltcd".

Constraints:

• 1 ⇐ word.length ⇐ 105

• word consists of lowercase English letters.

思路分析

一刷

link:{sourcedir}/_2063_VowelsOfAllSubstrings.java[role=include]

参考资料