285. Inorder Successor in BST

[Shawngbk]

还是递归的方法，因为是BST，当p的val>= 当前root的val时，就要在root的right一侧寻找。如果p的val小于root的val，就要在左侧找到第一个值。 /**

• Definition for a binary tree node.
• public class TreeNode {
• int val;
• TreeNode left;
• TreeNode right;
• TreeNode(int x) { val = x; }

• } */ public class Solution { TreeNode res; public TreeNode inorderSuccessor(TreeNode root, TreeNode p) { res = null; helper(root, p); return res; }

  private void helper(TreeNode root, TreeNode p) { if(root != null) { if(root.val <= p.val) { helper(root.right, p); } else { res = root; helper(root.left, p); } } } }

[Shawngbk]