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 inStr) {
        // write code here
            Stack<Character> stack = new Stack<>();
            Boolean flag = true;
            for(int i=0;i<inStr.length();i++){
                char c = inStr.charAt(i);
                if (c == '(' || c == '[' || c == '{') {
                    stack.push(c);
                    continue;
                }
                if(stack.empty()){
                    flag = false;
                    break;
                }
                char c1 = stack.pop();
                if(c == ')' && c1 != '('){
                    flag = false;
                    break;
                }
                if(c == ']' && c1 != '['){
                    flag = false;
                    break;
                }
                if(c == '}' && c1 != '{'){
                    flag = false;
                    break;
                }
            }
            if(!stack.empty()){
                flag = false;
            }
            return flag;        
    }
}