How to Solve Number of Valid Words in a Sentence Problem
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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 mo...
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Understanding the Number of Valid Words in a Sentence Problem
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Problem Statement
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).
Number of Valid Words in a Sentence
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Examples
sentence = "cat and dog"3The valid words in the sentence are "cat", "and", and "dog".
sentence = "!this 1-s b8d!"0There are no valid words in the sentence. "!this" is invalid because it starts with a punctuation mark. "1-s" and "b8d" are invalid because they contain digits.
sentence = "alice and bob are playing stone-game10"5The valid words in the sentence are "alice", "and", "bob", "are", and "playing". "stone-game10" is invalid because it contains digits.
Constraints
1 <= sentence.length <= 1000sentence only contains lowercase English letters, digits, ' ', '-', '!', '.', and ','.There will be at least 1 token.How Interview Coder Helps with Leetcode Problems
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