java括号匹配问题介绍

public boolean isValid(String s) {
        Stack<Character> stack = new Stack<>();
        for(int i = 0;i<s.length();i++){
            char ch = s.charAt(i);
            if(ch=='('||ch=='['||ch=='{'){
                stack.push(ch);//左括号进栈
            }else{
                if(stack.empty()){//栈为空，右括号多了
                    return false;
                }else{
                    char ch1 = stack.peek();//取栈顶元素
                if(ch1=='('&& ch ==')'||ch1=='{'&&ch=='}'||ch1=='['&&ch==']'){
                    stack.pop();//匹配出栈
                }else{
                    return false;//括号不匹配
                }
                }
            }
        }
        if(!stack.empty()){
            return false;//栈不为空，左括号偏多了
        }
        return true;
    }