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javab-tree

Reversed recursive traversal B-Tree


I have a B-Tree with a traverse function I found on GeeksForGeeks that does standard inorder traversal. I tried to modify it to do reversed inorder traversal by changing the for loop but it does not seem to work. Any ideas?

private void reversedInOrder(BTreeNode node) {
        int i;
        for (i = node.numNodes - 1; i >= 0; i--) {
            if (!node.isLeaf) {
                reversedInOrder(node.children[i]);
            }
            System.out.println(node.keys[i].getRedId());     
        }
        if (!node.isLeaf) {
            reversedInOrder(node.children[i]);
        }
    }

Solution

  • I after some more debugging I figured out the problem. Here is the solution. Seems like my indices were off.

    private void reversedInOrder(BTreeNode node) {
            int i;
            for (i = node.numNodes; i > 0; i--) {
                if (!node.isLeaf) {
                    reversedInOrder(node.children[i]);
                }
                if (node.keys[i - 1] != null) {
                    System.out.println(node.keys[i - 1].getName());
                }
            }
            if (!node.isLeaf) {
                reversedInOrder(node.children[i]);
            }
        }