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linked.go
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linked.go
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package linked
import (
"github.com/catorpilor/leetcode/utils"
)
// MyLinkedList wraps utils.ListNode
type MyLinkedList struct {
Head *utils.ListNode
N int
}
func (ll *MyLinkedList) String() string {
if ll.Head.Next != nil {
return ll.Head.Next.String()
}
return ""
}
// Constructor creates MyLinkedList
func Constructor() *MyLinkedList {
return &MyLinkedList{Head: &utils.ListNode{}}
}
// Get returns the ith node'value
func (ll *MyLinkedList) Get(index int) int {
if index < 0 || index >= ll.N {
return -1
}
var idx int
cur := ll.Head
for idx <= index {
cur = cur.Next
idx++
}
return cur.Val
}
// AddAtHead add a new head
func (ll *MyLinkedList) AddAtHead(val int) {
ll.AddAtIndex(0, val)
}
// AddAtTail add a new node at the end
func (ll *MyLinkedList) AddAtTail(val int) {
ll.AddAtIndex(ll.N, val)
}
// AddAtIndex at a new node at index with val, time complelxity O(N)
func (ll *MyLinkedList) AddAtIndex(index int, val int) {
if index > ll.N || index < 0 {
return
}
ll.N++
prev := ll.Head
for i := 0; i < index; i++ {
prev = prev.Next
}
node := &utils.ListNode{Val: val, Next: prev.Next}
prev.Next = node
}
// DeleteAtIndex delete a node at index
func (ll *MyLinkedList) DeleteAtIndex(index int) {
if index < 0 || index >= ll.N {
return
}
ll.N--
prev := ll.Head
for i := 0; i < index; i++ {
prev = prev.Next
}
prev.Next = prev.Next.Next
}