链表的冒泡排序

题目

public class ListNode{
int val;
ListNode next;

public ListNode(int val) {
this.val = val;
}
}

分析

public ListNode Bubble(ListNode root){
ListNode Head = root;

int length = 0;
while (root != null){
root = root.next;
length++;
}

int index = 0;
while (index < length -1){
ListNode cur = Head;
ListNode pre = null;
for (int i = 0; i < length - 1 - index; i++) {
ListNode temp = cur.next;
if (temp.val < cur.val){//exchange
cur.next = temp.next;
temp.next = cur;
if (pre == null){//头指针情况
pre = temp;
Head = pre;
}else {
pre.next = temp;
pre = temp;
}
}else {
pre = cur;
cur = temp;
}
}
index++;
}
return Head;
}