63 lines
1.7 KiB
Java
63 lines
1.7 KiB
Java
package com.leetcode.string;
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import java.util.HashMap;
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import java.util.Map;
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import java.util.Stack;
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/**
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* 给定一个只包括 '('，')'，'{'，'}'，'['，']' 的字符串 s ，判断字符串是否有效。
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有效字符串需满足：
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左括号必须用相同类型的右括号闭合。
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左括号必须以正确的顺序闭合。
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来源：力扣（LeetCode）
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链接：https://leetcode-cn.com/problems/valid-parentheses
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著作权归领扣网络所有。商业转载请联系官方授权，非商业转载请注明出处。
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*/
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public class IsValidKuoHao {
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private static Map<Character, Character> kuohao = new HashMap<Character, Character>() {
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/**
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*
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*/
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private static final long serialVersionUID = 1L;
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{
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put('(', ')');
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put('{', '}');
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put('[', ']');
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}};
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public boolean isValid(String s) {
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Stack<Character> stack = new Stack<>();
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for (int i = 0; i < s.length(); i++) {
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char c = s.charAt(i);
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if (stack.empty()) {
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stack.push(c);
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continue;
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}
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Character pre = stack.peek();
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if (pre == null || kuohao.get(pre) == null) {
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stack.push(c);
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continue;
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}
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if (kuohao.get(pre) == c) {
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stack.pop();
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} else {
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stack.push(c);
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}
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}
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return stack.empty();
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}
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public static void main(String[] args) {
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IsValidKuoHao validKuoHao = new IsValidKuoHao();
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String str = "{[]}";
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boolean isValid = validKuoHao.isValid(str);
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System.out.println(isValid);
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}
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}
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