BinarySearchTree

[arastuthakur]

// Binary Search Tree operations in C

#include <stdio.h>
#include <stdlib.h>

struct node {
int key;
struct node *left, *right;
};

// Create a node
struct node *newNode(int item) {
struct node *temp = (struct node *)malloc(sizeof(struct node));
temp->key = item;
temp->left = temp->right = NULL;
return temp;
}

// Inorder Traversal
void inorder(struct node *root) {
if (root != NULL) {
// Traverse left
inorder(root->left);

// Traverse root
printf("%d -> ", root->key);

// Traverse right
inorder(root->right);

}
}

// Insert a node
struct node *insert(struct node *node, int key) {
// Return a new node if the tree is empty
if (node == NULL) return newNode(key);

// Traverse to the right place and insert the node
if (key < node->key)
node->left = insert(node->left, key);
else
node->right = insert(node->right, key);

return node;
}

// Find the inorder successor
struct node *minValueNode(struct node *node) {
struct node *current = node;

// Find the leftmost leaf
while (current && current->left != NULL)
current = current->left;

return current;
}

// Deleting a node
struct node *deleteNode(struct node *root, int key) {
// Return if the tree is empty
if (root == NULL) return root;

// Find the node to be deleted
if (key < root->key)
root->left = deleteNode(root->left, key);
else if (key > root->key)
root->right = deleteNode(root->right, key);

else {
// If the node is with only one child or no child
if (root->left == NULL) {
struct node *temp = root->right;
free(root);
return temp;
} else if (root->right == NULL) {
struct node *temp = root->left;
free(root);
return temp;
}

// If the node has two children
struct node *temp = minValueNode(root->right);

// Place the inorder successor in position of the node to be deleted
root->key = temp->key;

// Delete the inorder successor
root->right = deleteNode(root->right, temp->key);

}
return root;
}

// Driver code
int main() {
struct node *root = NULL;
root = insert(root, 8);
root = insert(root, 3);
root = insert(root, 1);
root = insert(root, 6);
root = insert(root, 7);
root = insert(root, 10);
root = insert(root, 14);
root = insert(root, 4);

printf("Inorder traversal: ");
inorder(root);

printf("\nAfter deleting 10\n");
root = deleteNode(root, 10);
printf("Inorder traversal: ");
inorder(root);
}