LeetCode20. 有效的括号isValid（栈）

1、题目描述

2、代码详解

import java.util.Stack;

public class IsValid_20 {
    public static void main(String[] args){
        String s = "{[]}";
        System.out.println(isValid(s));
    }

    public static boolean isValid(String s){
        Stack<Character> stack = new Stack<>();
        for (char c : s.toCharArray()){
            if(c == '(' || c == '{' || c == '[') {
                stack.push(c);
            }
            else {
                if (stack.isEmpty())
                    return false;
                char cStack = stack.pop();
                boolean b1 = (c == ')' && cStack != '(');
                boolean b2 = (c == '}' && cStack != '{');
                boolean b3 = (c == ']' && cStack != '[');
                if (b1 || b2 || b3) // 如果不匹配
                    return false;
            }
        }
        return stack.isEmpty();
    }
}