java 669.修剪二进制搜索Tree.java

Posted 2021-05-08

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
    
    public TreeNode trimBST(TreeNode root, int L, int R) {
        if (root == null) return null;
        if (root.val < L) return trimBST(root.right, L, R);
        else if (root.val > R) return trimBST(root.left, L, R);
        else {
            root.left = trimBST(root.left, L, R);
            root.right = trimBST(root.right, L, R);
        }
        return root;
        
    }
}