669. Trim a Binary Search Tree

原题链接

/** * Created by Joe on 2017/12/14. * https://leetcode.com/problems/trim-a-binary-search-tree/description/ */public class P669 {    public TreeNode trimBST(TreeNode root, int L, int R) {        if (root == null) return null;        if (root.val < L) return trimBST(root.right, L, R);        if (root.val > R) return trimBST(root.left, L, R);        root.left = trimBST(root.left, L, R);        root.right = trimBST(root.right, L, R);        return root;    }}