题解 | 杨辉三角的变形

#include <iostream>

using namespace std;

int main(){
    int n;
    cin>>n;
    if(n <= 2){
        cout << -1 << endl;
    }else{
        switch(n % 4){
            case 0:
                cout<<3<<endl;
                break;
            case 1:
                cout<<2<<endl;
                break;
            case 2:
                cout<<4<<endl;
                break;
            case 3:
                cout<<2<<endl;
                break;
        }
    }
    return 0;
}