题解 | #xxx定律#

//
// Created by alleyf on 2023/6/24.
//
#include<bits/stdc++.h>

using namespace std;

int xxx_law(int& num, int& cnt) {
    if (num == 1) {
        return cnt;
    } else if (num % 2 != 0) {
        cnt++;
        num = 3 * num + 1;
        num /= 2;
        return xxx_law(num, cnt);
    } else {
        cnt++;
        num /= 2;
        return xxx_law(num, cnt);
    }
}

int main() {
    int num;
    while (cin >> num) {
        int cnt = 0;
        cout << xxx_law(num, cnt) << endl;
    }
}

> 递归求解容易理解，亦可使用while迭代求解。