一、题目内容

二、题解

解法1：

思路

堆栈，比较

代码

public class Solution {
    /**
     * 
     * @param s string字符串 
     * @return bool布尔型
     */
    public boolean isValid (String s) {
        // write code here
        if(s == null || s.length()%2!=0){
            return false;
        }
        Stack<Character> stack = new Stack<Character>();
        char[] chars = s.toCharArray();
        for(char c: chars){
            if(c == '{' || c=='('||c=='['){
                stack.add(c);
            }else{
                if(!stack.isEmpty()){
                    Character pop = stack.pop();
                    if (c == ')') {
                        if (pop != '(') {
                            return false;
                        }
                    } else if (c == '}') {
                        if (pop != '{') {
                            return false;
                        }
                    } else if (c == ']') {
                        if (pop != '[') {
                            return false;
                        }
                    }
                }else{
                    return false;
                }
            }
        }
        return stack.isEmpty();
    }
}