public static Node treeToList(Node root) { // base case: empty tree -> empty list if (root==null) return(null); // Recursively do the subtrees (leap of faith!) Node aList = treeToList(root.small); Node bList = treeToList(root.large); // Make the single root node into a list length-1 // in preparation for the appending root.small = root; root.large = root; // At this point we have three lists, and it's // just a matter of appending them together // in the right order (aList, root, bList) aList = append(aList, root); aList = append(aList, bList); return(aList); }
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