发现是二叉搜索树,递归写起来更简单
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
if (root == null) return -1;
int s = root.val;
if ((s <= p && s >= q) || (s >= p && s <= q)) return s;
if (s < p && s < q) return lowestCommonAncestor(root.right, p, q);
else return lowestCommonAncestor(root.left, p, q);
}
}