题目链接:https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=614
Time limit: 3.000 seconds

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

Problem solving report:

Description: 给你由'[',']','(',')'组成的字符串，问能否进行括号匹配。
Problem solving: 利用栈的性质，只要遇到能匹配的就移出栈，否则就进栈，最后再判断一下栈是否为空就行了。

#include <stack>
#include <cstdio>
#include <algorithm>
using namespace std;
int main()
{
    int t;
    char str[130];
    scanf("%d%*c", &t);
    while (t--)
    {
        gets(str);
        stack <char> s;
        for (int i = 0; str[i]; i++)
        {
            if (!s.empty())
            {
                if ((s.top() != '[' || str[i] != ']') && (s.top() != '(' || str[i] != ')'))
                    s.push(str[i]);
                else s.pop();
            }
            else s.push(str[i]);
        }
        if (!s.empty())
            printf("No\n");
        else printf("Yes\n");
    }
    return 0;
}