Tree data structure

Binary Search Tree - Implementation Struct Node{ int data; Node *left; Node *right; }; Nodes will be created in heap using malloc function

Binary Search Tree - Implementation Struct Node{ int data; Node *left; Node *right; }; Nodes will be created in heap using malloc function

Binary Search Tree - Implementation in C

//To search an element in BST, returns true if element is found #include<stdio.h> #include<stdlib.h> //Definition of Node for Binary search tree struct node { int data; struct node* left; struct node* right; }; // Function to create a new Node in heap struct node* GetNewNode(int data) { struct node* newNode = (struct node*)malloc(sizeof(struct node)); newNode->data = data; newNode->left = newNode->right = NULL; return newNode; //return the address of the newly created node } // To insert data in BST, returns address of root node struct node* Insert(struct node* root,int data) { if(root == NULL) { // empty tree root = GetNewNode(data); // if data to be inserted is lesser, insert in left subtree. else if(data <= root->data) { root->left = Insert(root->left,data); // else, insert in right subtree. else { root->right = Insert(root->right,data); return root; //To search an element in BST, returns true if element is found int Search(struct node* root,int data) { if(root == NULL) { return 0; } else if(root->data == data) { return 1; else if(data <= root->data) { return Search(root->left,data); else { return Search(root->right,data); int main() { struct node* root = NULL; // Creating an empty tree /*Evaluating the logic of the code*/ root = Insert(root,15); root = Insert(root,10); root = Insert(root,20); root = Insert(root,25); root = Insert(root,8); root = Insert(root,12); // Ask user to enter a number. int number; printf("Enter number be searched\n"); scanf("%d",&number); //If number is found, print "FOUND" if(Search(root,number) == 1) printf("Found\n"); else printf("Not Found\n");

Binary Tree Traversal Array Linked List Linear Data Structure Tree traversal is the process of visiting each node in the tree exactly once in some order Visit Reading/Processing data in a node Head

Binary Tree Traversal Three Common Tree Traversals Preorder Inorder Postorder

Tree Traversal Breadth First Depth First Breadth-First: P, D, J, B, E, G, K, A, C, I, Y Depth-First: 3 Strategies Preorder (Root, Left-Subtree, Right-Subtree): P, D, B, A, C, E, J, G, I, Y, K Inorder (Left-subtree, Root, Right-subtree): A, B, C, D, E, P, G, Y, I, J, K Postorder (Left-subtree, Right-subtree, Root): A, C, B, E, D, Y, I, G, K, J, P

Preorder Binary Tree Traversal Visit the root. Traverse the left subtree, i.e., call Preorder(left-subtree) Traverse the right subtree, i.e., call Preorder(right-subtree) #include<stdio.h> #include<stdlib.h> //Definition of Node for Binary search tree struct node { int data; struct node* left; struct node* right; }; // Recursive Function to print BST in Preorder void Preorder(struct node* root) { if (root == NULL) return; /* first print data of node */ printf("%d ", root->data); /* then recur on left sutree */ Preorder(root->left); /* now recur on right subtree */ Preorder(root->right); }

Inorder Binary Tree Traversal Traverse the left subtree, i.e., call Inorder(left-subtree) Visit the root. Traverse the right subtree, i.e., call Inorder(right-subtree) #include<stdio.h> #include<stdlib.h> //Definition of Node for Binary search tree struct node { int data; struct node* left; struct node* right; }; // Recursive Function to print BST in Inorder void Inorder(struct node* root) { if (root == NULL) return; /* first recur on left child */ Inorder(root->left); /* then print the data of node */ printf("%d ", root->data); /* now recur on right child */ Inorder(root->right); }

Postorder Binary Tree Traversal Traverse the left subtree, i.e., call Postorder(left-subtree) Traverse the right subtree, i.e., call Postorder(right-subtree) Visit the root. #include<stdio.h> #include<stdlib.h> //Definition of Node for Binary search tree struct node { int data; struct node* left; struct node* right; }; // Recursive Function to print BST in Postorder void Postorder(struct node* root) { if (root == NULL) return; // first recur on left subtree Postorder(root->left); // then recur on right subtree Postorder(root->right); // now deal with the node printf("%d ", root->data); }

Delete a node from BST

else if(root->left == NULL) { struct Node *temp = root; /* Deleting a node from Binary search tree */ #include<stdio.h> #include<stdlib.h> struct Node { int data; struct Node *left; struct Node *right; }; //Function to find minimum in a tree. Node* FindMin(Node* root) { while(root->left != NULL) root = root->left; return root; } // Function to search a delete a value from tree. struct Node* Delete(struct Node *root, int data) { if(root == NULL) return root; else if(data < root->data) root->left = Delete(root->left,data); else if (data > root->data) root->right = Delete(root->right,data); // Yippe... I found you, Get ready to be deleted else { // Case 1: No child if(root->left == NULL && root->right == NULL) { free (root); root = NULL; //Case 2: One child else if(root->left == NULL) { struct Node *temp = root; root = root->right; free (temp); } else if(root->right == NULL) { root = root->left; // case 3: 2 children else { struct Node *temp = FindMin(root->right); root->data = temp->data; root->right = Delete(root->right,temp->data); return root; //Function to visit nodes in Inorder void Inorder(Node *root) { if(root == NULL) return; Inorder(root->left); //Visit left subtree printf("%d ",root->data); //Print data Inorder(root->right); // Visit right subtree // Function to Insert Node in a Binary Search Tree Node* Insert(Node *root,char data) { if(root == NULL) { root = new Node(); root->data = data; root->left = root->right = NULL; else if(data <= root->data) root->left = Insert(root->left,data); else root->right = Insert(root->right,data);

int main() { /*Code To Test the logic Creating an example tree 5 / \ 3 10 / \ \ 1 4 11 */ Node* root = NULL; root = Insert(root,5); root = Insert(root,10); root = Insert(root,3); root = Insert(root,4); root = Insert(root,1); root = Insert(root,11); // Deleting node with value 5, change this value to test other cases root = Delete(root,5); //Print Nodes in Inorder printf("Inorder: "); Inorder(root); printf("\n"); }

free (root); root = NULL; //Case 2: One child /* Deleting a node from Binary search tree */ #include<stdio.h> #include<stdlib.h> struct Node { int data; struct Node *left; struct Node *right; }; //Function to find minimum in a tree. Node* FindMin(Node* root) { while(root->left != NULL) root = root->left; return root; } // Function to search a delete a value from tree. struct Node* Delete(struct Node *root, int data) { if(root == NULL) return root; else if(data < root->data) root->left = Delete(root->left,data); //from Delete(200,15) (1) else if (data > root->data) root->right = Delete(root- >right,data); //return is 350 (6) // Yippe... I found you, Get ready to be deleted else { // Case 1: No child //(5) if(root->left == NULL && root->right == NULL) { free (root); root = NULL; //Case 2: One child else if(root->left == NULL) { struct Node *temp = root; root = root->right; free (temp); } else if(root->right == NULL) { root = root->left; // case 3: 2 children //from Delete(350,15) (2) else { struct Node *temp = FindMin(root->right); root->data = temp->data; //Replace 15 by 17 (3) root->right = Delete(root->right,temp->data); //Delete(400,17) (4) ->return is NULL through step 5 } } return root; //Function to visit nodes in Inorder void Inorder(Node *root) { if(root == NULL) return; Inorder(root->left); //Visit left subtree printf("%d ",root->data); //Print data Inorder(root->right); // Visit right subtree // Function to Insert Node in a Binary Search Tree Node* Insert(Node *root,char data) { if(root == NULL) { root = new Node(); root->data = data; root->left = root->right = NULL; else if(data <= root->data) root->left = Insert(root->left,data); else root->right = Insert(root->right,data);