Brackets! Brackets! hrbust (运用栈) 

 1 #include<stdio.h>
 2 #include<string.h>
 3 #define MAX 110
 4 int main()
 5 {
 6     char stack[MAX];
 7     int top,n,i,flag;
 8     char a[MAX];
 9     scanf("%d",&n);
10     while(n--)
11     {
12          top=-1;
13          flag=0;
14         scanf("%s",a);
15         for(i=0;i<strlen(a);i++)
16         {
17             if(a[i]=='('||a[i]=='['||a[i]=='{')
18                 stack[++top]=a[i];
19             else
20             {
21             if(top>=0&&((a[i]==')'&&stack[top]=='(')||(a[i]==']'&&stack[top]=='[')||(a[i]=='}'&&stack[top]=='{')))
22              top--;
23             else
24             {
25               flag=1;
26               break;
27             }//注意这个语句的作用与下面的if的关系，你知道栈，但你不一定能很好的做这道题
28             }
29         }
30         if(!flag&&top==-1)
31             printf("Valid\n");
32         else
33             printf("Invalid\n");
34     }
35     return 0;
36 }

 

Total Submit: 171(40 users) Total Accepted: 49(33 users) Special Judge: No
Description

There are six kinds of brackets: ‘(‘, ‘)’, ‘[‘, ‘]’, ‘{’, ‘}’. dccmx’s girl friend is now learning java programming language, and got mad with brackets! Now give you a string of brackets. Is it valid? For example: “(([{}]))” is valid, but “([)]” is not.
Input

First line contains an integer T (T<=10): the number of test case.

Next T lines, each contains a string: the input expression consists of brackets.

The length of a string is between 1 and 100.
Output

For each test case, output “Valid” in one line if the expression is valid, or “Invalid” if not.
Sample Input
2
{{[[(())]]}}
({[}])
Sample Output
Valid
Invalid
posted @ 2012-09-18 20:18  尔滨之夏  阅读(248)  评论(0)  编辑  收藏  举报