UVA 673 Parentheses Balance 解题心得

原题

Description

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

分析：简单题，直接用栈就可以

我的代码：

 1 #include<iostream>
 2 #include<stack>
 3 #include<cstring>
 4 #include<cstdio>
 5 using namespace std;
 6
 7 char s[150];
 8
 9 bool ifpop(const char a, const char b)
10 {
11     if (a == ‘(‘&&b == ‘)‘)            return 1;
12     if (a == ‘[‘&&b == ‘]‘)            return 1;
13     return 0;
14 }
15
16
17 int main()
18 {
19     int t;
20     cin >> t;
21     getchar();
22     while (t--)
23     {
24         stack<char> z;
25         gets(s);
26         if (s[0] == ‘\0‘)
27         {
28             puts("Yes");
29             continue;
30         }
31         else
32         {
33             for (int i = 0;s[i]!=‘\0‘; i++)
34             {
35                 if (z.empty())
36                 {
37                     z.push(s[i]);
38                 }
39                 else
40                 {
41                     if (ifpop(z.top(), s[i]))
42                     {
43                         z.pop();
44                     }
45                     else
46                     {
47                         z.push(s[i]);
48                     }
49                 }
50             }
51             if (z.empty())                puts("Yes");
52             else                        puts("No");
53         }
54
55
56     }
57     return 0;
58 }