// C/C++ program to find longest consecutive // sequence in binary tree #include    using namespace std; /* A binary tree node has data pointer to left  child and a pointer to right child */ struct Node {  int data;  Node *left *right; }; // A utility function to create a node Node* newNode(int data) {  Node* temp = new Node;  temp->data = data;  temp->left = temp->right = NULL;  return temp; } // Utility method to return length of longest // consecutive sequence of tree void longestConsecutiveUtil(Node* root int curLength  int expected int& res) {  if (root == NULL)  return;  // if root data has one more than its parent  // then increase current length  if (root->data == expected)  curLength++;  else  curLength = 1;  // update the maximum by current length  res = max(res curLength);  // recursively call left and right subtree with  // expected value 1 more than root data  longestConsecutiveUtil(root->left curLength  root->data + 1 res);  longestConsecutiveUtil(root->right curLength  root->data + 1 res); } // method returns length of longest consecutive // sequence rooted at node root int longestConsecutive(Node* root) {  if (root == NULL)  return 0;  int res = 0;  // call utility method with current length 0  longestConsecutiveUtil(root 0 root->data res);  return res; } // Driver code to test above methods int main() {  Node* root = newNode(6);  root->right = newNode(9);  root->right->left = newNode(7);  root->right->right = newNode(10);  root->right->right->right = newNode(11);  printf('%dn' longestConsecutive(root));  return 0; } 

// Java program to find longest consecutive  // sequence in binary tree class Node {  int data;  Node left right;  Node(int item)  {  data = item;  left = right = null;  } } class Result  {  int res = 0; } class BinaryTree {  Node root;  // method returns length of longest consecutive   // sequence rooted at node root   int longestConsecutive(Node root)  {  if (root == null)  return 0;  Result res = new Result();    // call utility method with current length 0   longestConsecutiveUtil(root 0 root.data res);    return res.res;  }  // Utility method to return length of longest   // consecutive sequence of tree   private void longestConsecutiveUtil(Node root int curlength   int expected Result res)  {  if (root == null)  return;  // if root data has one more than its parent   // then increase current length   if (root.data == expected)  curlength++;  else  curlength = 1;  // update the maximum by current length   res.res = Math.max(res.res curlength);  // recursively call left and right subtree with   // expected value 1 more than root data   longestConsecutiveUtil(root.left curlength root.data + 1 res);  longestConsecutiveUtil(root.right curlength root.data + 1 res);  }  // Driver code  public static void main(String args[])   {  BinaryTree tree = new BinaryTree();  tree.root = new Node(6);  tree.root.right = new Node(9);  tree.root.right.left = new Node(7);  tree.root.right.right = new Node(10);  tree.root.right.right.right = new Node(11);  System.out.println(tree.longestConsecutive(tree.root));  } } // This code is contributed by shubham96301 

# Python3 program to find longest consecutive  # sequence in binary tree  # A utility class to create a node  class newNode: def __init__(self data): self.data = data self.left = self.right = None # Utility method to return length of  # longest consecutive sequence of tree  def longestConsecutiveUtil(root curLength expected res): if (root == None): return # if root data has one more than its  # parent then increase current length  if (root.data == expected): curLength += 1 else: curLength = 1 # update the maximum by current length  res[0] = max(res[0] curLength) # recursively call left and right subtree  # with expected value 1 more than root data  longestConsecutiveUtil(root.left curLength root.data + 1 res) longestConsecutiveUtil(root.right curLength root.data + 1 res) # method returns length of longest consecutive  # sequence rooted at node root  def longestConsecutive(root): if (root == None): return 0 res = [0] # call utility method with current length 0  longestConsecutiveUtil(root 0 root.data res) return res[0] # Driver Code if __name__ == '__main__': root = newNode(6) root.right = newNode(9) root.right.left = newNode(7) root.right.right = newNode(10) root.right.right.right = newNode(11) print(longestConsecutive(root)) # This code is contributed by PranchalK 

// C# program to find longest consecutive  // sequence in binary tree  using System;  class Node  {   public int data;   public Node left right;   public Node(int item)   {   data = item;   left = right = null;   }  }  class Result  {   public int res = 0;  }  class GFG  {   Node root;   // method returns length of longest consecutive   // sequence rooted at node root   int longestConsecutive(Node root)   {   if (root == null)   return 0;   Result res = new Result();     // call utility method with current length 0   longestConsecutiveUtil(root 0 root.data res);     return res.res;   }   // Utility method to return length of longest   // consecutive sequence of tree   private void longestConsecutiveUtil(Node root int curlength   int expected Result res)   {   if (root == null)   return;   // if root data has one more than its parent   // then increase current length   if (root.data == expected)   curlength++;   else  curlength = 1;   // update the maximum by current length   res.res = Math.Max(res.res curlength);   // recursively call left and right subtree with   // expected value 1 more than root data   longestConsecutiveUtil(root.left curlength   root.data + 1 res);   longestConsecutiveUtil(root.right curlength   root.data + 1 res);   }   // Driver code   public static void Main(String []args)   {   GFG tree = new GFG();   tree.root = new Node(6);   tree.root.right = new Node(9);   tree.root.right.left = new Node(7);   tree.root.right.right = new Node(10);   tree.root.right.right.right = new Node(11);   Console.WriteLine(tree.longestConsecutive(tree.root));   }  }  // This code is contributed by 29AjayKumar 

<script> // JavaScript program to find longest consecutive  // sequence in binary tree class Node {  constructor(item)  {  this.data=item;  this.left = this.right = null;  } } let res = 0; let root; function longestConsecutive(root) {  if (root == null)  return 0;    res=[0];     // call utility method with current length 0   longestConsecutiveUtil(root 0 root.data res);    return res[0]; }  // Utility method to return length of longest   // consecutive sequence of tree  function longestConsecutiveUtil(rootcurlength expectedres) {  if (root == null)  return;    // if root data has one more than its parent   // then increase current length   if (root.data == expected)  curlength++;  else  curlength = 1;    // update the maximum by current length   res[0] = Math.max(res[0] curlength);    // recursively call left and right subtree with   // expected value 1 more than root data   longestConsecutiveUtil(root.left curlength   root.data + 1 res);  longestConsecutiveUtil(root.right curlength   root.data + 1 res); } // Driver code root = new Node(6); root.right = new Node(9); root.right.left = new Node(7); root.right.right = new Node(10); root.right.right.right = new Node(11); document.write(longestConsecutive(root)); // This code is contributed by rag2127 </script>