JuniorString
Number of Valid Words in a Sentence
A sentence consists of lowercase letters ('a' to 'z'), digits ('0' to '9'), hyphens ('-'), punctuation marks ('!', '.', and ','), and spaces (' ') only. Each sentence can be broken down into one or more tokens separated by one or more spaces ' '.
A token is a valid word if all three of the following are true:
- It only contains lowercase letters, hyphens, and/or punctuation (no digits).
- There is at most one hyphen
'-'. If present, it must be surrounded by lowercase characters ("a-b"is valid, but"-ab"and"ab-"are not valid). - There is at most one punctuation mark. If present, it must be at the end of the token (
"ab,","cd!", and"."are valid, but"a!b"and"c.,"are not valid).
Examples of valid words include "a-b.", "afad", "ba-c", "a!", and "!".
Given a string sentence, return the number of valid words in sentence.
Example 1
Input
sentence = "cat and dog"Output
3The valid words in the sentence are "cat", "and", and "dog".
Example 2
Input
sentence = "!this 1-s b8d!"Output
0There are no valid words in the sentence because "!this" starts with a punctuation mark, while "1-s" and "b8d!" contain digits.
Constraints
- 1 <= sentence.length <= 1000
- sentence only contains lowercase English letters, digits, ' ', '-', '!', '.', and ','.
- There will be at least 1 token.