题解 | #有效括号序列#

import java.util.*;


public class Solution {
    /**
     *
     * @param s string字符串
     * @return bool布尔型
     */
    public boolean isValid (String s) {
        // write code here
        if (s.length() % 2 != 0) {
            return false;
        }

        LinkedList<Character> stack = new LinkedList<>();

        char[] toCharArray = s.toCharArray();
        for (char aChar : toCharArray) {
            if (aChar == '(' || aChar == '{' || aChar == '[') {
                stack.push(aChar);
            } else if (aChar == ')') {
                if (stack.isEmpty() || stack.pop() != '(') {
                    return false;
                }
            } else if (aChar == '}') {
                if (stack.isEmpty() || stack.pop() != '{') {
                    return false;
                }
            } else if (aChar == ']') {
                if (stack.isEmpty() || stack.pop() != '[') {
                    return false;
                }
            }
        }
        return stack.isEmpty();
    }
}