算法题：n个括号的合法全排列

#include <iostream>#include <string.h>#include <stack>using namespace std;//n个括号的合法全排列.bool Grial(char *str){    stack<char> st;    char *p = str;    while (*p != '\0')    {        if (*p == '(')        {            st.push(*p);        }        if (*p == ')')        {            if (st.empty() == true)            {                st.push(*p);            }            else if (st.top() == '(')                st.pop();            else return false;        }        p++;    }    return st.empty() != false;}void Grial(char * p,char * str,char *s,int x,int n){    if (x==n)    {        *str = '\0';        if (Grial(p))        cout << p << endl;        return;    }    for (int i = 0; i < 2; i++)    {        *str = s[i];        Grial(p,str+1, s,x+1,n);    }}int main(){    char s[] = "()";    int n;    cout << "请输入括号个数：" << endl;    cin >> n;    if (n < 2 && n % 2 != 0)    {        cout << "你的输入有误" << endl;        return -1;    }    char *str = new char[n];    memset(str,'0',sizeof(str));    Grial(str,str,s,0,n);    return 0;}