#include <iostream>
#include<vector>
using namespace std;
int cnt=0;
string a[10]={"xie","wang","song","guo","liu","he","1","2","3","4"};//全局變量，便於變量函數間操作
void printv(vector<string> &v)//輸出函數
{
for(int i=0;i<v.size();i++)
{
cout<<v[i]<<endl;
}
cout<<endl<<endl<<endl;
}
int small(int n,vector<string> &v)//統計起始循環值
{
for(int i=0;i<n;i++)
{
if(a[i]==v.back())
{
return i;
}
}
}
void pick(int n,vector<string> &v,int topick)//核心代碼
{
if(topick==0)//調用輸出
{
cnt++;
printv(v);
return;//極爲關鍵，跳出層層遞歸值力氣，萬不可缺
}
int start;
if(v.empty())//統計起始循環值
{
start=0;
}
else{
start=small(n,v)+1;
}
for(int j=start;j<n;j++)//核心中的核心，topick層遞歸，逐層跳出，區別於迭代，迭代是分支枚舉，遞歸是深度搜索
{
v.push_back(a[j]);
pick(n,v,topick-1);
v.pop_back();
}
}
int main()
{
vector<string>v;
pick(10,v,5);
cout<<cnt;
}