Method convertToSumTree

16_BinaryTrees/SumTree.java:13–26

(Node root)

    }

    public static int convertToSumTree(Node root) {
        if(root == null) {
            return 0;
        }
        
        int leftVal = convertToSumTree(root.left);
        int rightVal = convertToSumTree(root.right);
        int leftSubtree = root.left == null ? 0 : root.left.data;
        int rightSubtree = root.right == null ? 0 : root.right.data;
        
        int myData = root.data;
        root.data = leftSubtree + leftVal + rightSubtree + rightVal;
        return myData;
    }

    public static void preorder(Node root) {
        if(root == null) {