题解 | 有效括号序列

import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param s string字符串 
     * @return bool布尔型
     */
    public boolean isValid (String s) {
        // write code here
        Stack<Character> zhan = new Stack<Character>();
        for(int i = 0; i < s.length() ; i ++){
            if(zhan.isEmpty()){
                zhan.push(s.charAt(i));
                continue;
            }
            Character ding = zhan.peek();
            Character cur = s.charAt(i);
            if( ding == '(' && cur == ')' ){
                zhan.pop();
                continue;
            }
            if( ding == '[' && cur == ']' ){
                zhan.pop();
                continue;
            }
            if( ding == '{' && cur == '}' ){
                zhan.pop();
                continue;
            }
            zhan.push(cur);
        }
        return zhan.isEmpty();
    }
}