反向链接列表的策略 [英] strategies to reverse a linked list in JavaScript
问题描述
我只是在一个简单的面试问题中苦苦挣扎:请扭转一个单链表.
I just struggled through a simple interview question: Please reverse a singly linked list.
虽然我未能及时提供有效的答案来保存面试,但后来我能够提出解决方案.
While I failed to provide a working answer in time to save the interview, I was able to come up with a solution afterwards.
我的解决方案正确吗?您将如何使用Big-Oh对此进行分析?是否有更有效的方法来反转单链列表?
Is my solution correct? How would you analyze this with Big-Oh? Are there more efficient ways to reverse a singly linked list?
// reverse a linked list
var reverseLinkedList = function(linkedlist) {
var node = linkedlist;
var previous = null;
while(node) {
// reverse pointer
node.next = previous;
// increment previous to current node
previous = node;
// increment node to next node
if (node.next){
node = node.next
} else {
node = null;
}
}
}
注意:在搜索相似的帖子时,我确实在JavaScript中找到了一个示例.我想知道我的代码是否可行(没有temp
变量).谢谢.
Note: In my search for similar posts, I did find one example in JavaScript. I was wondering if my code is possible (without a temp
variable). Thank you.
推荐答案
您的代码有两个问题.这应该很清楚.
There are a couple of problems with your code. This should make it clear.
// reverse a linked list
var reverseLinkedList = function(linkedlist) {
var node = linkedlist;
var previous = null;
while(node) {
// save next or you lose it!!!
var save = node.next;
// reverse pointer
node.next = previous;
// increment previous to current node
previous = node;
// increment node to next node or null at end of list
node = save;
}
return previous; // Change the list head !!!
}
linkedlist = reverseLinkedList(linkedlist);
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