回溯法输出所有出栈序列

//回溯法输出所有出栈序列
#include 
using namespace std;
int tot, res, sta, n;
int r[2005], s[2005];
void recall(int m){
	if(m == n + 1){//若所有元素都入过栈，输出当前出栈序列
		tot++;
		cout << "Case #" << tot << ":" << endl;
		for(int i = 1; i <= res; i++){
			cout << r[i] << ' ';
		}
		for(int i = sta; i > 0; i--){
			cout << s[i] << ' ';
		}
		cout << endl;
		return;
	}
	if(sta > 0){
		r[++res] = s[sta];
		sta--;
		recall(m);//栈顶元素出栈
		s[++sta] = r[res];
		res--;//回溯操作
	}
	s[++sta] = m;//当前元素入栈
	recall(m + 1);
	sta--;//回溯操作
}
int main(){
	cin >> n;
	tot = 0;res = 0;sta = 0;
	recall(1);
	cout << "There are total " << tot << " sequences.";
	return 0;
}