LeetCode & Q20-Valid Parentheses-Easy

转载于 2017-07-28 11:28:00 发布 · 99 阅读

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原文链接：http://www.cnblogs.com/duyue6002/p/7249298.html

本文介绍了一种使用栈数据结构来验证包含括号的字符串是否有效的算法。通过遍历字符串并利用栈来检查括号是否正确配对，实现了一个简单的括号匹配验证器。

Stack String

Description:

Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.

The brackets must close in the correct order, "()" and "()[]{}" are all valid but "(]" and "([)]" are not.

堆栈的典型例子

my Solution:

public class Solution {
    public boolean isValid(String s) {
        Deque<Character> stack = new ArrayDeque<>();
        if (s.length() == 0)
            return true;
        else {
            for (int i = 0; i < s.length(); i++) {
                Character ch = s.charAt(i);
                if (!stack.isEmpty()) {
                    Character temp = stack.peek();
                    if ((temp == '(' && ch == ')') || (temp == '[' && ch == ']') || (temp == '{' && ch == '}')) {
                        stack.pop();
                    } else {
                        stack.push(ch);
                    }
                } else {
                    stack.push(ch);
                }
            }
        }
        return stack.isEmpty();
    }
}

转载于:https://www.cnblogs.com/duyue6002/p/7249298.html