题解 | #二叉搜索树的最近公共祖先#

import java.util.*;

/*
 * public class TreeNode {
 *   int val = 0;
 *   TreeNode left = null;
 *   TreeNode right = null;
 *   public TreeNode(int val) {
 *     this.val = val;
 *   }
 * }
 */

public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param root TreeNode类 
     * @param p int整型 
     * @param q int整型 
     * @return int整型
     */
    public int lowestCommonAncestor (TreeNode root, int p, int q) {
        // write code here
        int low = Math.min(p, q);
        int high = Math.max(p, q);
        return search(root, low, high);
    }

    private int search(TreeNode root, int low, int high) {
        if (root.val >= low && root.val <= high) {
            return root.val;
        }

        if (root.val >= high) {
            return search(root.left, low, high);
        }

        return search(root.right, low, high);
    }
}