Given the head of a linked list, remove the nth node from the end of the list and return its head.
Follow up: Could you do this in one pass?
Example 1:
Input: head = [1,2,3,4,5], n = 2 Output: [1,2,3,5]
Example 2:
Input: head = [1], n = 1 Output: []
Example 3:
Input: head = [1,2], n = 1 Output: [1]
Constraints:
- The number of nodes in the list is
sz. 1 <= sz <= 300 <= Node.val <= 1001 <= n <= sz
struct Solution;
use rustgym_util::*;
impl Solution {
fn remove_nth_from_end(mut head: ListLink, n: i32) -> ListLink {
let mut v: Vec<ListLink> = vec![];
while let Some(mut node) = head {
head = node.next.take();
v.push(Some(node));
}
let mut res = None;
for (i, link) in v.into_iter().rev().enumerate() {
if i != (n - 1) as usize {
let mut node = link.unwrap();
node.next = res;
res = Some(node);
}
}
res
}
}
#[test]
fn test() {
let head = list![1, 2, 3, 4, 5];
let res = list![1, 2, 3, 5];
let n = 2;
assert_eq!(Solution::remove_nth_from_end(head, n), res);
}