对链表进行合并排序 [英] Merge Sort a Linked List
本文介绍了对链表进行合并排序的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我最近复习了一些基础知识,发现对链表进行合并排序是一个很好的挑战.如果你有一个很好的实现,那么在这里展示它.
I was recently brushing up on some fundamentals and found merge sorting a linked list to be a pretty good challenge. If you have a good implementation then show it off here.
推荐答案
想知道为什么这里所说的它应该是一个巨大的挑战,这里是一个简单的 Java 实现,没有任何聪明的技巧".
Wonder why it should be big challenge as it is stated here, here is a straightforward implementation in Java with out any "clever tricks".
//The main function
public static Node merge_sort(Node head)
{
if(head == null || head.next == null)
return head;
Node middle = getMiddle(head); //get the middle of the list
Node left_head = head;
Node right_head = middle.next;
middle.next = null; //split the list into two halfs
return merge(merge_sort(left_head), merge_sort(right_head)); //recurse on that
}
//Merge subroutine to merge two sorted lists
public static Node merge(Node a, Node b)
{
Node dummyHead = new Node();
for(Node current = dummyHead; a != null && b != null; current = current.next;)
{
if(a.data <= b.data)
{
current.next = a;
a = a.next;
}
else
{
current.next = b;
b = b.next;
}
}
dummyHead.next = (a == null) ? b : a;
return dummyHead.next;
}
//Finding the middle element of the list for splitting
public static Node getMiddle(Node head)
{
if(head == null)
return head;
Node slow = head, fast = head;
while(fast.next != null && fast.next.next != null)
{
slow = slow.next;
fast = fast.next.next;
}
return slow;
}
这篇关于对链表进行合并排序的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文