87 lines
2.1 KiB
Rust
87 lines
2.1 KiB
Rust
/**
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* [20] Valid Parentheses
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*
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* Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.
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* An input string is valid if:
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* <ol>
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* Open brackets must be closed by the same type of brackets.
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* Open brackets must be closed in the correct order.
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* Every close bracket has a corresponding open bracket of the same type.
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* </ol>
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*
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* <strong class="example">Example 1:
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*
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* Input: s = "()"
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* Output: true
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*
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* <strong class="example">Example 2:
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*
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* Input: s = "()[]{}"
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* Output: true
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*
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* <strong class="example">Example 3:
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*
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* Input: s = "(]"
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* Output: false
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*
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*
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* Constraints:
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*
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* 1 <= s.length <= 10^4
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* s consists of parentheses only '()[]{}'.
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*
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*/
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pub struct Solution {}
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// problem: https://leetcode.cn/problems/valid-parentheses/
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// discuss: https://leetcode.cn/problems/valid-parentheses/discuss/?currentPage=1&orderBy=most_votes&query=
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// submission codes start here
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impl Solution {
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pub fn is_valid(s: String) -> bool {
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let left = vec!['(', '[', '{'];
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let right = vec![')', ']', '}'];
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let mut stack = Vec::with_capacity(s.len());
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for c in s.chars() {
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if left.contains(&c) {
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stack.push(c)
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} else if right.contains(&c) {
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let target = match c {
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')' => '(',
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']' => '[',
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'}' => '{',
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_ => return false,
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};
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if stack.ends_with(&[target]) {
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stack.pop();
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} else {
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return false;
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}
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} else {
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return false;
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}
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}
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stack.is_empty()
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}
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}
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// submission codes end
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn test_20() {
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assert_eq!(true, Solution::is_valid(String::from("()")));
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assert_eq!(true, Solution::is_valid(String::from("()[]{}")));
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assert_eq!(false, Solution::is_valid(String::from("(]")));
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assert_eq!(false, Solution::is_valid(String::from("(")));
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}
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}
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