problem0707

README

707. Design Linked List

题目

Design yourimplementation of the linked list. You can choose to use the singly linked list or the doubly linked list. A node in a singlylinked list should have two attributes: valand next. val is the value of the current node, and nextisapointer/reference to the next node. If you want to use the doubly linked list,you will needone more attribute prev to indicate the previous node in the linked list. Assume all nodes in the linked list are 0-indexed.

Implement these functions in your linked list class:

• get(index) : Get the value ofthe index-thnode in the linked list. If the index is invalid, return -1.
• addAtHead(val) : Add a node of value valbefore the first element of the linked list. After the insertion, the new node will be the first node of the linked list.
• addAtTail(val) : Append a node of value valto the last element of the linked list.
• addAtIndex(index, val) : Add a node of value valbefore the index-thnode in the linked list.If indexequalsto the length oflinked list, the node will be appended to the end of linked list. If index is greater than the length, the node will not be inserted.
• deleteAtIndex(index) : Deletethe index-thnode in the linked list, if the index is valid.

Example:

MyLinkedList linkedList = new MyLinkedList();
linkedList.addAtHead(1);
linkedList.addAtTail(3);
linkedList.addAtIndex(1, 2);  // linked list becomes 1->2->3
linkedList.get(1);            // returns 2
linkedList.deleteAtIndex(1);  // now the linked list is 1->3
linkedList.get(1);         // returns 3

Note:

• All values will be in the range of [1, 1000].
• The number of operations will be in the range of[1, 1000].
• Please do not use the built-in LinkedList library.

解题思路

见程序注释

Documentation

Index

• type MyLinkedList
  • func Constructor() MyLinkedList
  • func (l *MyLinkedList) AddAtHead(val int)
  • func (l *MyLinkedList) AddAtIndex(index int, val int)
  • func (l *MyLinkedList) AddAtTail(val int)
  • func (l *MyLinkedList) DeleteAtIndex(index int)
  • func (l *MyLinkedList) Get(index int) int

Types

type MyLinkedList

type MyLinkedList struct {
	// contains filtered or unexported fields
}

MyLinkedList object will be instantiated and called as such: obj := Constructor(); param_1 := obj.Get(index); obj.AddAtHead(val); obj.AddAtTail(val); obj.AddAtIndex(index,val); obj.DeleteAtIndex(index);

func Constructor

func Constructor() MyLinkedList

Constructor initialize your data structure here. */

func (*MyLinkedList) AddAtHead

func (l *MyLinkedList) AddAtHead(val int)

AddAtHead a node of value val before the first element of the linked list. After the insertion, the new node will be the first node of the linked list.

func (*MyLinkedList) AddAtIndex

func (l *MyLinkedList) AddAtIndex(index int, val int)

AddAtIndex add a node of value val before the index-th node in the linked list. If index equals to the length of linked list, the node will be appended to the end of linked list. If index is greater than the length, the node will not be inserted.

func (*MyLinkedList) AddAtTail

func (l *MyLinkedList) AddAtTail(val int)

AddAtTail append a node of value val to the last element of the linked list.

func (*MyLinkedList) DeleteAtIndex

func (l *MyLinkedList) DeleteAtIndex(index int)

DeleteAtIndex delete the index-th node in the linked list, if the index is valid.

func (*MyLinkedList) Get

func (l *MyLinkedList) Get(index int) int

Get the value of the index-th node in the linked list. If the index is invalid, return -1. */