栈—summertraining#2.A题

You are given a string consisting of parentheses () and []. A string of this type is said to be correct:

(a): if it is the empty string
(b): if A and B are correct, AB is correct,
(c): if A is correct, (A ) and [A ] is correct.

Write a program that takes a sequence of strings of this type and check their correctness. Your program can assume that the maximum string length is 128.

Input

The file contains a positive integer n and a sequence of n strings of parentheses () and [], one string a line.

Output

A sequence of Yes or No on the output file.

Sample Input

3
([])
(([()])))
([()[]()])()

Sample Output

Yes
No
Yes

代码如下：

 1 #include<iostream>
 2 #include<stdio.h>
 3 #include<stack>
 4 #include<string.h>
 5 using namespace std;
 6 
 7 int main()
 8 {
 9     int n;
10     while(scanf("%d",&n)!=EOF)
11     {
12         char stack[128];
13         char str[128];
14         getchar();      //由于gets()把换行符当做结束字符，注意用getchar()吸收换行符。
15         while(gets(str))
16         {
17             
18             int i,top=-1;
19             for(i=0;i<strlen(str) ;i++)
20             {
21                 if(str[i]=='('|| str[i]=='[')
22                     stack[++top]=str[i];
23                 
24                 
25                 if(str[i]==')' && stack[top]!='(')
26                 {  
27                     top=0;
28                     break;
29                 }
30                 else if(str[i]==']' && stack[top]!='[')
31                 {
32                     top=0;
33                     break;
34                 }
35                 
36                 if(str[i]==')' && stack[top]=='(')
37                    top--;
38                 
39                 else if(str[i]==']' && stack[top]=='[')
40                     top--;
41             
42                 
43             }
44             
45             if(top==-1)
46                 printf("Yes
");
47             else
48                 printf("No
");
49         }
50     }
51     
52     return 0;
53 }

本来要求是要自己实现栈的操作，可是不熟悉自己写不了，只好用STL暂时先过了题。还参考了大神的代码，看了好几天的书百度很多栈的相关用法，栈的数组表示和栈的代码实现。虽说已经学了一年的C和C++，可感觉自己很不熟悉对于竞赛题恐惧极了。现在在重新补充学习C和C++。无论怎样，每天都要比昨天的自己懂得更多，即使进步微乎其微，也不要轻易放弃。看不见希望是很恐怖难过的事，不被看好也没关系，自己啊，要握住生命的绳不被左右不被打乱pace。

第二周马上要结束了，总结。恩。