create ListNode from Vec with ref to first Node - rust

Question

#[derive(PartialEq, Eq, Clone, Debug)]
pub struct ListNode {
pub val: i32,
pub next: Option<Box<ListNode>>,
}
impl ListNode {
#[inline]
fn new(val: i32) -> Self {
ListNode { next: None, val }
}
}
fn create_list(list : Vec<i32>) -> Option<Box<ListNode>> {
// the code should be written this place
}
i have ListNode struct like this and dont't want to edit this struct and impl. i get a list of i32 number as Vec and i want to create ListNode that each item in list point next item and at the end return first number
for example get vector like this [1,2,3]
and at the end return object like this (i want to create programmatically and this is hand made)
ListNode {
val : 1,
ListNode {
val : 2,
next:ListNode {
next: None,
val : 3
}
}
}
i can't hold first ListNode and return that while dealing with rust borrowing and ownership
-- Update --
i am new to rust. so i create an example from the way i want to solve this problem. this example written in typescript
class ListNode {
val: number
next: ListNode | null
constructor(val?: number, next?: ListNode | null) {
this.val = (val===undefined ? 0 : val)
this.next = (next===undefined ? null : next)
}
toString(): string {
return `ListNode ${this.val}${this.next===null? "" : ' => '+ this.next.toString()}`
}
}
function createList(list : number[]) : ListNode|null {
const firstItem = new ListNode(0,null);
let second = firstItem;
for (let item of list) {
second.next = new ListNode(item,null)
second = second.next;
}
return firstItem.next;
}
const firstNodePointer = createList([1,2,3,4,5])
console.log(firstNodePointer?.toString())

Answer 1

This will create the list in one go.
fn create_list(list : Vec<i32>) -> Option<Box<ListNode>> {
let mut head = None;
let mut current = &mut head;
for x in list {
*current = Some(Box::new(ListNode::new(x)));
current = &mut current.as_mut().unwrap().next;
}
head
}