Delete node in a linked list - leetcode python
Delete Node in a Linked ListWrite a function to delete a node (except the tail) in a singly linked list, given only access to that node. Supposed the linked list is1 -> 2 -> 3 -> 4and you are given the third node with value3, the linked list should become1 -> 2 -> 4after calling your function. Analysis:To solve this problem, the key point is "overwrite" ! Usually we are thinking "skip" the node we want to delete by: 1 -> 2 -> 3 -> 4 -> Null, delete 3, we have: 1 -> 2--------> 4 -> Null. However in this problem, the previous node is unknown. So, what we should do is to overwrite the node "3" by node "4": 1 -> 2 -> 3 -> 4->Null, delete 3, we have: 1 -> 2 -> 4->Null. Just pay attention to the case that the node is the last node. Code(C++):/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {} * }; */ class Solution { public: void deleteNode(ListNode* node) { if (node->next){ node->val = node->next->val; node->next = node->next->next; }else{ node = NULL; } } }; Code(Python):# Definition for singly-linked list. # class ListNode(object): # def __init__(self, x): # self.val = x # self.next = None class Solution(object): def deleteNode(self, node): """ :type node: ListNode :rtype: void Do not return anything, modify node in-place instead. """ if node.next: node.val = node.next.val node.next = node.next.next else: node = None |
