题解 | #杨辉三角的变形#

#include <iostream>
using namespace std;

int main() {
    int n;
    cin>>n;
    if(n<3)
    {
        cout<<-1;
    }
    else{
        if(n%2==1)
        {
            cout<<2<<endl;
        }
        else if(n%2==0)
        {
            int out;
            if(n%4==0){//画出来找规律；也可以递推出第n行的vector<int>,比较麻烦
                out=3;
            }
            else if(n%4!=0){
                out=4;

            }
            cout<<out<<endl;
        }
    } 
}
// 64 位输出请用 printf("%lld")