Adding InOrderSuccessorInBST

Author: Sahilkumar19

InOrderSuccessorInBST.java

@@ -0,0 +1,66 @@
+/*
+Given the root of a binary search tree and a node p in it, return the in-order successor of that node in the BST. If the
+given node has no in-order successor in the tree, return null.
+The successor of a node p is the node with the smallest key greater than p.val.
+
+Example 1:
+Input: root = [2,1,3], p = 1
+Output: 2
+Explanation: 1's in-order successor node is 2. Note that both p and the return value is of TreeNode type.
+
+Algorithm
+
+If the value of the root node is less than or equal to the value of the p node, it means that the successor
+node of p must be in the right subtree, so this function is recursively called on the right child node.
+If the value of the root node is greater than the value of p, then it is possible that the root node is the
+successor of p, or a node in the left subtree is a successor of p, * So first call this function recursively
+on the left child node, * If it returns empty, indicating that the root node is a successor node, just return,
+* If it is not empty, return that node
+
+ */
+
+public class InOrderSuccessorInBST {
+    public static void main(String[] args) {
+        TreeNode root=new TreeNode(50);
+        root.left=new TreeNode(20);
+        root.right=new TreeNode(100);
+        root.left.left=new TreeNode(10);
+        root.left.right=new TreeNode(30);
+        root.right.left=new TreeNode(80);
+        root.right.right=new TreeNode(110);
+        TreeNode ans=InOrderSuccessor(root,new TreeNode(110));
+        if (ans==null){
+            System.out.println(ans);
+        }
+        else {
+            System.out.println(ans.data);
+        }
+
+
+
+    }
+    public static TreeNode InOrderSuccessor(TreeNode root,TreeNode p){
+        if (root==null){
+            return null;
+        }
+        if (root.data<= p.data){
+            return InOrderSuccessor(root.right,p);
+        }
+        else {
+            TreeNode leftnode=InOrderSuccessor(root.left,p);
+            if (leftnode == null) {
+                return root;
+            } else {
+                return leftnode;
+            }
+        }
+        }
+    }
+class TreeNode{
+    int data;
+    TreeNode left,right;
+    public TreeNode(int key){
+        key=data;
+        left=right=null;
+    }
+}