练习：考拉兹序列

The Collatz Sequence is defined as follows, for an arbitrary n1 greater than zero:

  • If ni is 1, then the sequence terminates at ni.
  • If ni is even, then ni+1 = ni / 2.
  • If ni is odd, then ni+1 = 3 * ni + 1.

For example, beginning with n1 = 3:

  • 3 is odd, so n2 = 3 * 3 + 1 = 10;
  • 10 is even, so n3 = 10 / 2 = 5;
  • 5 is odd, so n4 = 3 * 5 + 1 = 16;
  • 16 is even, so n5 = 16 / 2 = 8;
  • 8 is even, so n6 = 8 / 2 = 4;
  • 4 is even, so n7 = 4 / 2 = 2;
  • 2 is even, so n8 = 1; and
  • 序列终止。

编写一个函数，用于计算给定初始 n 的考拉兹序列的长度。

/// Determine the length of the collatz sequence beginning at `n`.
fn collatz_length(mut n: i32) -> u32 {
  todo!("Implement this")
}

fn main() {
  todo!("Implement this")
}