Offer68_1.java

package com.yore.offer;

import com.yore.base.TreeNode;

/**
 * @author jia bing wen
 * @date 2021/7/6 16:17
 * @description
 */
public class Offer68_1 {
    public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
        if (p.val < root.val && q.val < root.val) {
            return lowestCommonAncestor(root.left, p, q);
        } else if (p.val > root.val && q.val > root.val) {
            return lowestCommonAncestor(root.right, p, q);
        }
        return root;
    }



    public TreeNode lowestCommonAncestor1(TreeNode root, TreeNode p, TreeNode q) {
        TreeNode ancestor = root;
        while (true) {
            if (p.val < ancestor.val && q.val < ancestor.val) {
                ancestor = ancestor.left;
            } else if (p.val > ancestor.val && q.val > ancestor.val) {
                ancestor = ancestor.right;
            } else {
                break;
            }
        }
        return ancestor;
    }

}