二叉树的深度搜索专题一＞二叉树剪枝

public TreeNode pruneTree(TreeNode root) {
        if(root == null) return root;
        root.left = pruneTree(root.left);
        root.right = pruneTree(root.right);
        if(root.left == null && root.right == null && root.val == 0)
            root = null;
        return root;     
    }