递归写法,非递归写法太麻烦,索性写了
import java.util.*;
/*
* public class TreeNode {
* int val = 0;
* TreeNode left = null;
* TreeNode right = null;
* }
*/
public class Solution {
/**
*
* @param root TreeNode类
* @param o1 int整型
* @param o2 int整型
* @return int整型
*/
public int lowestCommonAncestor (TreeNode root, int o1, int o2) {
// write code here
if (root == null) return -1;
if (root.val == o1 || root.val == o2) return root.val;
int left = lowestCommonAncestor(root.left, o1, o2);
int right = lowestCommonAncestor(root.right, o1, o2);
if (left != -1 && right != -1) return root.val;
if (left != -1 && right == -1) return left;
if (left == -1 && right != -1) return right;
return -1;
}
}