题解 | #xxx定律#

int main(){
    int a ;
    while (scanf("%d", &a) != EOF) {
        int count = 0;
        if (a == 0){
            return 0;
        }
        while (a != 1){
            if(a % 2 == 0){
                a /= 2;
            } else {
                a = (a * 3 + 1) / 2;
            }
            count ++;
        }
        printf("%d\n", count);
    }
}