我正在实施代码以构建BST(binary search tree)
,其中从this algorithm开始。我不回binary Search Tree
回来。我收到了一些毫无意义的东西。这里是我的代码从Java中的Post-order遍历构造二进制搜索树
public class BinaryTreemethods {
public static void main(String[] args) {
int[] preOrder = { 5, 3, 1, 4, 8, 6, 9 };
int[] inOrder = { 1, 3, 4, 5, 6, 8, 9 };
int[] postOrder = {1,4,3,8,6,9,5};
static int postIndex=postOrder.length-1;
Node postordertree= buildBinarytreefromPostOrder(postOrder, 0, postOrder.length-1);
System.out.println("pre order traversal of node from postorder reconstructed tree ");
printPreOrder(postordertree);
}
private static void printPreOrder(Node tree) {
if (tree != null) {
System.out.print(" " + tree.data);
printPreOrder(tree.left);
printPreOrder(tree.right);
}
}
//this just reconstructs BT from post-order traversal elements
public static Node buildBinarytreefromPostOrder(int[] post, int start, int end){
if (postIndex<start || start > end){
return null;
}
Node root = new Node(post[postIndex]);
postIndex--;
if (end == start){
//System.out.println("called");
return root;
}
int i = 0;
for (i=end;i>=start;i--){
if (post[i]<root.data)
break;
}
// Use the index of element found in postorder to divide postorder array
// in two parts. Left subtree and right subtree
root.right=buildBinarytreefromPostOrder(post,i+1, postIndex);
root.left=buildBinarytreefromPostOrder(post,start,i);
//root.left=buildBinarytreefromPostOrder(post,start,i);
//root.right=buildBinarytreefromPostOrder(post,i+1, postIndex);
return root;
}
}
,当我在pre-order traversal is 5 9 6 8 3 4
打印输出是不正确的。
任何想法,我可以去错了吗?
编辑:换行root.right and root.left
(注释掉之前), 行的顺序left tree
构建正确,但正确的树不是。我得到的输出是 5 3 1 4 9 6 8
您是否尝试过[调试代码(http://www.vogella.com/tutorials/EclipseDebugging/article.html)? – gerrytan
@gerrytan:ofcourse –