2021-03-14：手寫程式碼：單鏈表氣泡排序。

福大大 答案2021-03-14：

遍歷連結串列，算出元素個數，假設為N。需要巢狀迴圈，外迴圈N-1輪，每輪迴圈相鄰交換N-1次。

程式碼用golang編寫，程式碼如下：

package mainimport "fmt"func main() {    //head := &ListNode{Val: 4}    //head.Next = &ListNode{Val: 2}    //head.Next.Next = &ListNode{Val: 1}    //head.Next.Next.Next = &ListNode{Val: 3}    head := &ListNode{Val: -1}    head.Next = &ListNode{Val: 5}    head.Next.Next = &ListNode{Val: 3}    head.Next.Next.Next = &ListNode{Val: 4}    head.Next.Next.Next.Next = &ListNode{Val: 0}    cur := head    for cur != nil {        fmt.Print(cur.Val, "\t")        cur = cur.Next    }    fmt.Println()    head = BubbleSort(head)    cur = head    for cur != nil {        fmt.Print(cur.Val, "\t")        cur = cur.Next    }    fmt.Println()}//Definition for singly-linked list.type ListNode struct {    Val  int    Next *ListNode}//氣泡排序func BubbleSort(head *ListNode) *ListNode {    if head == nil || head.Next == nil {        return head    }    //連結串列節點的個數    count := 0    //對連結串列節點計數    temp := head.Next    for temp != nil {        count++        temp = temp.Next    }    //有換頭的可能，所以新增一個虛擬頭節點    preHead := &ListNode{Next: head}    //冒泡    var pre, cur *ListNode    for i := 0; i < count; i++ {        pre = preHead        cur = preHead.Next        for j := 0; j < count-i; j++ {            if cur.Val > cur.Next.Val {                //相鄰交換                pre.Next, cur.Next, cur.Next.Next, cur = cur.Next, cur.Next.Next, cur, cur.Next            }            pre = pre.Next            cur = cur.Next        }    }    //虛擬頭節點的Next指標就是需要返回的節點    return preHead.Next}

執行結果如下：

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[力扣148. 排序連結串列](https://leetcode-cn.com/problems/sort-list/)