NYOJ 2 括号配对问题 数据结构栈的应用

#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>#include <stack>using namespace std ;const int MAXN = 10005 ;char str[MAXN] ;bool flag ;void judge (){    int i ;    int len ;    char ch ;    stack <char> Q ;    len = strlen (str) ;    for (int i = 0; i < len; i ++)    {        if (Q.empty())        {            Q.push (str[i]) ;            continue ;        }        if (str[i] == '[' || str[i] == '(')            Q.push (str[i]) ;        else        {            if (str[i] == ']')            {                ch = Q.top () ;                Q.pop () ;                if (ch != '[')                {                    flag = false ;                    return ;                }            }            else            {                ch = Q.top () ;                Q.pop () ;                if (ch != '(')                {                    flag = false ;                    return ;                }            }        }    }    if (!Q.empty ())  // 如果此时栈中还有元素，肯定不匹配    {        flag = false ;        Q.pop () ;    }    return ;}int main(){    int tcase ;    scanf ("%d", &tcase) ;    while (tcase --)    {        scanf ("%s", str) ;        flag = true ;        judge () ;        if (flag)            printf ("Yes\n") ;        else            printf ("No\n") ;        memset (str, '\0', sizeof(str)) ;    }    return 0 ;}