代码随想录 Day23 - 二叉树（九）

package jjn.carl.binary_tree;
import commons.TreeNode;
/**
 * @author Jjn
 * @since 2023/8/1 16:36
 */
public class LeetCode669 {
    public TreeNode trimBST(TreeNode root, int low, int high) {
        if (root == null) {
            return null;
        }
        if (root.val < low) {
            return trimBST(root.right, low, high);
        }
        if (root.val > high) {
            return trimBST(root.left, low, high);
        }
        root.left = trimBST(root.left, low, high);
        root.right = trimBST(root.right, low, high);
        return root;
    }
}

package jjn.carl.binary_tree;
import commons.TreeNode;
/**
 * @author Jjn
 * @since 2023/8/1 17:08
 */
public class LeetCode108 {
    public TreeNode sortedArrayToBST(int[] nums) {
        return buildTree(nums, 0, nums.length - 1);
    }
    private TreeNode buildTree(int[] nums, int left, int right) {
        if (left > right) {
            return null;
        }
        int mid = left + (right - left) / 2;
        TreeNode root = new TreeNode(nums[mid]);
        root.left = buildTree(nums, left, mid - 1);
        root.right = buildTree(nums, mid + 1, right);
        return root;
    }
}

package jjn.carl.binary_tree;
import commons.TreeNode;
/**
 * @author Jjn
 * @since 2023/8/1 17:12
 */
public class LeetCode538 {
    private int sum = 0;
    public TreeNode convertBST(TreeNode root) {
        if (root != null) {
            convertBST(root.right);
            sum += root.val;
            root.val = sum;
            convertBST(root.left);
        }
        return root;
    }
}