zoukankan      html  css  js  c++  java
  • 19.1.29 [LeetCode 20] Valid Parentheses

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

    An input string is valid if:

    1. Open brackets must be closed by the same type of brackets.
    2. Open brackets must be closed in the correct order.

    Note that an empty string is also considered valid.

    Example 1:

    Input: "()"
    Output: true
    

    Example 2:

    Input: "()[]{}"
    Output: true
    

    Example 3:

    Input: "(]"
    Output: false
    

    Example 4:

    Input: "([)]"
    Output: false
    

    Example 5:

    Input: "{[]}"
    Output: true
     1 class Solution {
     2 public:
     3     bool isValid(string s) {
     4         stack<char>q;
     5         for (int i = 0; s[i]; i++) {
     6             if (s[i] == '(' || s[i] == '[' || s[i] == '{')
     7                 q.push(s[i]);
     8             else if (s[i] == ')'||s[i]==']'||s[i]=='}') {
     9                 if (q.empty())return false;
    10                 char c = q.top();
    11                 if (s[i] == ')') {
    12                     if (c == '(')q.pop();
    13                     else
    14                         return false;
    15                 }
    16                 else if (s[i] == ']') {
    17                     if (c == '[')q.pop();
    18                     else
    19                         return false;
    20                 }
    21                 else if (s[i] == '}') {
    22                     if (c == '{')q.pop();
    23                     else
    24                         return false;
    25                 }
    26             }
    27         }
    28         if (!q.empty())return false;
    29         return true;
    30     }
    31 };
    View Code
    注定失败的战争,也要拼尽全力去打赢它; 就算输,也要输得足够漂亮。
  • 相关阅读:
    感知器算法--python实现
    PHP appserv + ZendStudio12.5.1 + 注册码
    第九周-每周例行报告
    第八周-每周例行报告
    感谢THUNDER
    第七周-每周例行报告
    第六周-每周例行报告
    第五周-每周例行报告
    第四周-四则运算试题生成
    第四周-单元测试
  • 原文地址:https://www.cnblogs.com/yalphait/p/10333470.html
Copyright © 2011-2022 走看看