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/* Deleting a node from Binary search tree */ | |
#include<iostream> | |
using namespace std; | |
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); | |
// Wohoo... I found you, Get ready to be deleted | |
else { | |
// Case 1: No child | |
if(root->left == NULL && root->right == NULL) { | |
delete root; | |
root = NULL; | |
} | |
//Case 2: One child | |
else if(root->left == NULL) { | |
struct Node *temp = root; | |
root = root->right; | |
delete temp; | |
} | |
else if(root->right == NULL) { | |
struct Node *temp = root; | |
root = root->left; | |
delete temp; | |
} | |
// 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); | |
return root; | |
} | |
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 | |
cout<<"Inorder: "; | |
Inorder(root); | |
cout<<"\n"; | |
} |
It should return temp once deleted root in single child case
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Hey, I just want everyone to know that after Deleting a node from a BST, better check if the node is present or not by the
Search_Node
Function. Call theSearch_Node
function in the main function and check if the value returned by theSearch_Node
function istrue
orfalse.
Here is the Definition:
bool Search_Node(BstNode *root, int data)
{
if(root==NULL)
return false;
if(data==root->data)
return true;
else if(data>root->data)
return Search_Node(root->right, data);
else
return Search_Node(root->left, data);
}
Here's how you can check:
if(Search_Node(root, 20)==true) // here 20 is the data for the deleted node
printf("FOUND\n");
else
printf("NOT FOUND\n");