Valid Parenthesis String

Medium

Greedy · String · Stack~20m

00:00

Section 1Understand Problem

Section 01

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Problem statement

Given a string `s` containing only three types of characters: `'('`, `')'` and `'*'`, return `true` if `s` is valid. The following rules define a valid string: any left parenthesis `'('` must have a matching right parenthesis `')'`, any right parenthesis `')'` must have a matching left parenthesis `'('`, left parenthesis `'('` must go before the corresponding right parenthesis `')'`, and `'*'` could be treated as a single right parenthesis `')'` or a single left parenthesis `'('` or an empty string `""`.

Example

s = "()" → true

Constraints

1 ≤ s.length ≤ 100 · s[i] is '(', ')' or '*'

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