#include <bits/stdc++.h> using namespace std; int dp[30]; int main (){ freopen ("lcl.txt","r",stdin); int n; cin>>n; dp[1]=0; dp[2]=1; dp[3]=2; for (int i=4; i<=n; i++){ dp[i]=(i-1)*(dp[i-1]+dp[i-2]); } cout<<dp[n]<<endl; return 0; }
我为啥只有六十分呢?