汉诺塔 - JavaScript的 - 好的部分 [英] Tower Of Hanoi - JavaScript - THe Good Parts

问题描述

我见过的其他问题上的SO关于递归函数，我已经阅读了反应，但我还是不能让算法来点击我的头

I have seen the other Questions on SO about the Recursive function and I have read the responses but I still can't get the algorithm to click in my head

var hanoi = function (disc, src, aux, dst) {

  if (disc > 0) {
    hanoi(disc - 1, src, dst, aux);
   document.write('Move disc ' + disc + ' from ' + src + ' to ' + dst);
    hanoi(disc - 1, aux, src, dst);
  }
}

hanoi(3, 'Src', 'Aux', 'Dst');

如何进行的document.write（...），曾运行。我的逻辑是我们第一次运行该函数光盘> 3.然后我们递归调用函数再次跳过下面让一切如何执行document.write得到运行机会呢？

How does the document.write(...), ever run. My Logic is First time we run the function disc is > 3. then we recursively call the function again skipping everything below so how does the document.write get a chance to run?

据我了解递归（做了基本的例子），但我还是不能看你怎么得到的输出。如果有一种方法，我可以运行它直观地看到它在行动，这将有助于很多。

I understand recursion (done the basic examples) but i still can't see how you get an output. If there is a way i can run it visually and see it in action, that would help alot.

推荐答案

您能想到的会发生什么事是调用树（从上一次移动到下）：

You can think of what will happen as a call tree (time moves from top to bottom):

hanoi(3, ...) =>
 |-> hanoi(2, ...) =>
 |    |-> hanoi(1, ...) =>
 |    |    |-> hanoi(0, ...) =>
 |    |    |    \-> (does nothing)
 |    |    |-> document.write(...)
 |    |    |-> hanoi(0, ...) =>
 |    |    |    \-> (does nothing)
 |    |  <-/ [hanoi(1, ...) finished]
 |    |-> document.write(...)
 |    |-> hanoi(1, ...) =>
 |    |    |-> hanoi(0, ...) =>
 |    |    |    \-> (does nothing)
 |    |    |-> document.write(...)
 |    |    |-> hanoi(0, ...) =>
 |    |    |    \-> (does nothing)
 |    |  <-/ [hanoi(1, ...) finished]
 |  <-/ [hanoi(2, ...) finished]
 |-> document.write(...) [halfway done!]
 |-> hanoi(2, ...) =>
 |    \-> [same pattern as the first time, with different data]
 \-> [hanoi(3, ...) finished]

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