提交时间:2023-10-05 10:18:39

运行 ID: 105089

#include<bits/stdc++.h> using namespace std; int num,a[10001],n; bool b[10001]; inline void print() { num++; for(int i=1;i<=n;++i) cout<<a[i]; cout<<endl; } inline void dfs(int k) { for(int i=1;i<=n;++i) if(!b[i]) { a[k]=i, b[i]=1; (k==n)?print():dfs(k+1); b[i]=0; } } signed main() { cin>>n; dfs(1); cout<<num; return 0; }