java 括号匹配 成对

import java.util.Stack;

public class Solution {

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

        //栈的特性：先进后出(后进先出 LIFO Last In First Out) 压栈 弹栈 
        Stack<Character> stack = new Stack<>();

        for (int i = 0; i < s.length(); i++) {

            char c = s.charAt(i);
            if (c == '(' || c == '[' || c == '{') {
                stack.push(c);
            } else {
                if (stack.isEmpty())
                    return false;

                char topChar = stack.pop();
                //如果c 源值是 ( 且目标值不是反向C 表示两者并不是对立关系  返回false  匹配完必须是空
                if (c == ')' && topChar != '(') {
                    return false;
                }

                if (c == ']' && topChar != '[') {
                    return false;
                }

                if (c == '}' && topChar != '{') {
                    return false;
                }
            }
        }
        return stack.isEmpty();
    }
}