题解 | #有效括号序列#

import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param s string字符串
     * @return bool布尔型
     */
    public boolean isValid (String s) {
        // write code here
        char[] a = s.toCharArray();
        ArrayDeque<Character> stack = new ArrayDeque<>();
        int i = 0;
        while (i < a.length) {
            if (a[i] == '{' || a[i] == '[' || a[i] == '(') {
                stack.push(a[i]);
                i++;
                continue;
            }
            if (a[i] == '}') {
                if (stack.isEmpty()) {
                    return false;
                }
                if (stack.pop() != '{') {
                    return false;
                }
                i++;
                continue;
            }
            if (a[i] == ']') {
                if (stack.isEmpty()) {
                    return false;
                }
                if (stack.pop() != '[') {
                    return false;

                }
                i++;
                continue;
            }
            if (a[i] == ')') {
                if (stack.isEmpty()) {
                    return false;
                }
                if (stack.pop() != '(') {
                    return false;

                }
                i++;
                continue;
            }

            i++;
        }
        return stack.isEmpty();

    }
}