876. Middle of the Linked List

Given a non-empty, singly linked list with head node head, return a middle node of linked list.

If there are two middle nodes, return the second middle node.

Example 1:

Input: [1,2,3,4,5]
Output: Node 3 from this list (Serialization: [3,4,5])
The returned node has value 3.  (The judge's serialization of this node is [3,4,5]).
Note that we returned a ListNode object ans, such that:
ans.val = 3, ans.next.val = 4, ans.next.next.val = 5, and ans.next.next.next = NULL.

Example 2:

Input: [1,2,3,4,5,6]
Output: Node 4 from this list (Serialization: [4,5,6])
Since the list has two middle nodes with values 3 and 4, we return the second one.

Note:

• The number of nodes in the given list will be between 1 and 100.

876. Middle of the Linked List
struct Solution;
use rustgym_util::*;

struct List {
}

impl List {
List { head }
}

fn middle(&self) -> &ListLink {
let mut slow = &self.head;
let mut fast = &self.head;
while fast.is_some() && fast.as_ref().unwrap().next.is_some() {
slow = &slow.as_ref().unwrap().next;
fast = &fast.as_ref().unwrap().next.as_ref().unwrap().next;
}
slow
}
}

impl Solution {
let list = List::new(head);
let middle: &ListLink = list.middle();
middle.clone()
}
}

#[test]
fn test() {
let head = list![1, 2, 3, 4, 5];
let middle = list![3, 4, 5];