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) {
        boolean result = true;
        // String s="([])";
        Map<Character, Character> symbol = new HashMap<>();
        symbol.put('(', ')');
        symbol.put('[', ']');
        symbol.put('{', '}');
        Stack<Character> deq = new Stack<>();
        Stack<Character> cache = new Stack<>();
        for (int i = 0; i < s.length(); i++) {
            if (symbol.values().contains(s.charAt(i))
                    || symbol.keySet().contains(s.charAt(i))) {
                deq.push(s.charAt(i));
            }
        }
        if (deq.size() % 2 != 0) {
            return false;
        }
        while (!deq.isEmpty()) {
            Character lastSym = deq.pop();
            if (symbol.values().contains(lastSym)) {
                cache.push(lastSym);
                continue;
            }
            if (symbol.keySet().contains(lastSym)) {
                if(cache.isEmpty()){
                    result=false;
                    break;
                }

                Character endSym = cache.pop();

                if (Objects.isNull(endSym) || !endSym.equals(symbol.get(lastSym))) {
                    result = false;
                    break;
                }
            }
        }
        return result;
    }
}