概述
目标是将一个给定的列表向正确的方向旋转一定的位数。
例子
Input: 1->2->3->4->5
k: 2
Output: 4->5->1->2->3
程序
以下是相同的程序。
package main
import "fmt"
func main() {
first := initList()
first.AddFront(5)
first.AddFront(4)
first.AddFront(3)
first.AddFront(2)
first.AddFront(1)
first.Head.Traverse()
head := rotateRight(first.Head, 2)
fmt.Println("")
head.Traverse()
fmt.Println("")
}
func initList() *SingleList {
return &SingleList{}
}
type ListNode struct {
Val int
Next *ListNode
}
func (l *ListNode) Traverse() {
for l != nil {
fmt.Print(l.Val)
l = l.Next
}
}
type SingleList struct {
Len int
Head *ListNode
}
func (s *SingleList) Reverse() {
curr := s.Head
var prev *ListNode
var next *ListNode
for curr != nil {
next = curr.Next
curr.Next = prev
prev = curr
curr = next
}
s.Head = prev
}
func (s *SingleList) AddFront(num int) {
ele := &ListNode{
Val: num,
}
if s.Head == nil {
s.Head = ele
} else {
ele.Next = s.Head
s.Head = ele
}
s.Len++
}
func rotateRight(head *ListNode, k int) *ListNode {
if head == nil {
return nil
}
if k == 0 {
return head
}
lenList := 0
curr := head
var last *ListNode
for curr != nil {
lenList++
last = curr
curr = curr.Next
}
k = k % lenList
if k == 0 {
return head
}
curr = head
newHeadIndex := lenList - k
var prev *ListNode
for i := 0; i < newHeadIndex; i++ {
prev = curr
curr = curr.Next
}
newHeadNode := prev.Next
prev.Next = nil
last.Next = head
return newHeadNode
}
输出
12345
45123
