题解 | #牛牛的排列数#
牛牛的排列数
https://www.nowcoder.com/practice/9ca1c236cdbf46da9e08e1f510808625
#include <iostream>
using namespace std;
int arr_MN(int a,int b){
int A=1;
for(int i=1; i<=b; i++){ A *= a-i+1; }
return A;
if(A<0){return 0;}
}
int main() {
int n, m;
cin>>n;
cin>>m;
cout<<arr_MN(n, m);
return 0;
}
