Python:

a = int(input())
if a%2 == 0 :
    print("%d" % (a/2))
else:
    print("%d" % (a*3+1))

参考答案：

#include<iostream>

using namespace std;

int main()
{
    int a;
    cin >> a;

    if (a % 2 == 0) cout << a / 2;
    else cout << 3 * a + 1;

    return 0;
}