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POCan't print elements of BST at a given level in reverse order
 

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  1. POCan't print elements of BST at a given level in reverse order
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    <p>I am trying to write a code, which, given a Binary Search Tree root and a level, prints out the elements of the tree at that level. This is working fine:</p> <pre><code>def myprint(root,level): if root: if not level: print root.data, else: myprint(root.left,level-1) myprint(root.right,level-1) </code></pre> <p>However, when I try to tweak it to print the elements at a level in reverse order, it dosn't work. For the following tree:</p> <pre><code> 26 / \ 13 39 / \ / \ 6 19 32 51 / \ / \ / \ / \ 4 8 14 31 33 68 \ 17 </code></pre> <p>if I want to output the elements at level 3 (level of root is 0) from right to left, the output should be <code>68 33 31 14 8 4</code>. The code above does the reverse correctly, that is, prints out <code>4 8 14 31 33 68</code>. But the below code doesn't print the reverse order correctly, and prints out <code>31 33 68 4 8 14</code> instead:</p> <pre><code>def revprint(root,level): if root: if not level: print root.data, else: myprint(root.right,level-1) myprint(root.left,level-1) </code></pre> <p>Can anybody spot the error, and tell me how to rectify it? The code for initializing the tree is as follows:</p> <pre><code>class tree: def __init__(self,data): self.data = data self.successor,self.left,self.right = None,None,None def push(self,data): root = self while root: oldroot = root if root.data &gt; data: root = root.left elif root.data &lt; data: root = root.right if data &gt; oldroot.data: oldroot.right = tree(data) else: oldroot.left = tree(data) a = tree(26) for x in [13,39,6,19,4,8,5,10,9,14,17,15,32,51,68,31,33,36,34]: a.push(x) </code></pre>
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