237. Delete Node in a Linked List (Easy)
https://leetcode.com/problems/delete-node-in-a-linked-list/
Write a function to delete a node (except the tail) in a singly linked list, given only access to that node.
Given linked list -- head = [4,5,1,9], which looks like following:
Example 1:
Input: head = [4,5,1,9], node = 5 Output: [4,1,9] Explanation: You are given the second node with value 5, the linked list should become 4 -> 1 -> 9 after calling your function.
Example 2:
Input: head = [4,5,1,9], node = 1 Output: [4,5,9] Explanation: You are given the third node with value 1, the linked list should become 4 -> 5 -> 9 after calling your function.
Note:
- The linked list will have at least two elements.
- All of the nodes' values will be unique.
- The given node will not be the tail and it will always be a valid node of the linked list.
- Do not return anything from your function.
Solutions
class Solution {
public void deleteNode(ListNode node) {
ListNode p1 = node;
// as problem described, p2 should never be null
ListNode p2 = p1.next;
// a->b->c->p1->p2
// break until p2.next == null, not p2 == null
while (p2.next != null) {
p1.val = p2.val;
p1 = p2;
p2 = p2.next;
}
// Once get out from the loop, p2 != null, we need to move p2's
// value forward to p1
p1.val = p2.val;
p1.next = null;
}
}