/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
/*
找到的第一个节点,满足(root.val - p.val) * (root.val - q.val) < 0 ,则为LCA
*/
public class Solution {
public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
if (root == null || p == null || q == null) return null;
//if((root.val >= q.val && root.val <= p.val) || (root.val >= p.val && root.val <= q.val)) {
//return root;
while((root.val - (long)p.val) * (root.val - (long)q.val) > 0) {// in case of overflow
root = p.val < root.val ? root.left : root.right;
}
return root;
}
}
public class Solution {
public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
if (root == null || p == null || q == null) return root;
if (root.val > p.val && root.val > q.val) return lowestCommonAncestor(root.left, p, q);
if (root.val < p.val && root.val < q.val) return lowestCommonAncestor(root.right, p, q);
return root;
}
}