提交时间:2024-03-09 08:29:32

运行 ID: 136303

#include <bits/stdc++.h> using namespace std; const int N=1e2+10; const int INF=0x3f3f3f3f; int n,a[N],f[N],ans; void dfs(int x) { if(x==n) { for(int i=1; i<=x; i++) { cout<<a[i]; } cout<<endl; ans++; return; } for(int i=1; i<=n; i++) { if(f[i]==0) { f[i]=1; a[x+1]=i; dfs(x+1); f[i]=0; } a[x+1]=0; } } int main() { cin >> n; dfs(0); cout << ans; return 0; }