题意  判断输入的括号序列是否是配对的

栈的基础应用  栈顶元素与输入的字符匹配就出栈咯  注意括号序列可以为空

STL栈

#include <bits/stdc++.h>
using namespace std;
int main()
{
    int cas;
    char c;
    cin >> cas;
    getchar();
    while(cas--)
    {
        stack<char> s;
        while((c = getchar()) != '\n')
        {
            if(s.empty()) s.push(c);
            else  if((c == ')' && s.top() == '(')
                     || (c == ']' && s.top() == '['))
                s.pop();
            else s.push(c);
        }
        puts(s.empty() ? "Yes" : "No");
    }
    return 0;
}

#include<cstdio>
using namespace std;
int main()
{
    int cas, top;
    char s[200], c;
    scanf("%d", &cas);
    getchar();
    while(cas--)
    {
        top = 0;
        while((c = getchar()) != '\n')
        {
            if(top == 0) s[top++] = c;
            else if(s[top - 1] == '(' && c == ')'
                    || s[top - 1] == '[' && c == ']')
                --top;
            else s[top++] = c;
        }
        puts(top ? "No" : "Yes");
    }
    return 0;
}

Parentheses Balance

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

(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 

Output 

Sample Input 

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

Sample Output 

Yes
No
Yes

UVa 673 Parentheses Balance(括号配对 栈)