/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
class Solution {
public TreeNode inorderSuccessor(TreeNode root, TreeNode p) {
TreeNode successor = null;
while (root != null) {
if (p.val >= root.val) {
root = root.right;
} else {
successor = root;
root = root.left;
}
}
return successor;
}
}
/*
2
1 3
因為是 inorder, 所以是 left root right
所以往左走時, root 就是 potential successor （因為 left root
往右走則不是
*/