LeetCode 20 有效的括号

Posted 2021-12-14 Starzkg

https://leetcode-cn.com/problems/valid-parentheses/

解决方案

class Solution 
    public boolean isValid(String s) 
        Stack<Integer> stack = new Stack<>();
        stack.ensureCapacity(s.length());
        for (int i = 0; i < s.length(); i++) 
            int index = "([)]".indexOf(s.charAt(i));
            if (index <= 2) 
                stack.push(index);
             else if (stack.size() == 0 || stack.pop() != index % 3) 
                return false;
            
        
        return stack.size() == 0;