C: Create Binary Search Tree from a Array

Hi, Today we will create a Binary Search Tree, which is nothing but a Sorted Binary Tree. The methods which we have used here are:

1. Create Tree to iterate the Tree to the length of the array, with a reference to the array and to the root of the Tree
2. Create a Method to create a node and on the basis of the value at the index in the array and condition to put the node in the Tree should satisfy 
3. Print theTree

#include <stdio.h>

#include <stdlib.h>

struct BST

{

    struct BST* left;

    int info;

    struct BST* right;

};

void createTree(struct BST*, int*, int);

void makeNode(struct BST*, int*);

void printTree(struct BST*);

int main()

{

    int arr[100] = {6,5,3,7,9,4,1,10};

    struct BST* root = (struct BST*) malloc(sizeof(struct BST));

    root->info = arr[0];

    root->left = root->right = NULL;

    

    createTree(root, arr, 7);

    printTree(root);

    return 0;

}

void createTree(struct BST* root, int* arr_ref, int arr_len)

{

    struct BST* temproot = root;

    

    while(arr_len > 0)

    {

        arr_ref++;

        makeNode(temproot, arr_ref);

        arr_len--;

    }

}

void makeNode(struct BST* root, int* arr_ref)

{

    struct BST* temp = root;

    

        if(temp->info > *arr_ref)

        {

            if(temp->left == NULL)

            {

                struct BST* newnode = (struct BST*) malloc(sizeof(struct BST));

                newnode->info = *arr_ref;

                newnode->left = newnode->right = NULL;

                temp->left = newnode;

            }

            else

                makeNode(temp->left, arr_ref);

        }

        else if(temp->info <= *arr_ref)

        {

            if(temp->right == NULL)

            {

                struct BST* newnode = (struct BST*) malloc(sizeof(struct BST));

                newnode->info = *arr_ref;

                newnode->left = newnode->right = NULL;

                temp->right = newnode;

            }

            else

                makeNode(temp->right, arr_ref);

        }

}

void printTree(struct BST* root)

{

    struct BST* temp = root;

    

    if(temp == NULL)

        return;

    else

    {

        printTree(temp->left);

        printf(" %d ",temp->info);

        printTree(temp->right);

    }

}

Given a Binary Tree, replace the data of each node by the sum of data of all its descendent nodes.(Leaf nodes will have 0)

The Solution for this problem is simple and recursive one. In this problem you have to traverse to the last parent node which has at least 1 child.

So the conditions possible are:

1. Parent has only one leaf  node a) only Left Leaf Node or b) only Right Leaf Node
2. Parent has both children, Left and Right Leaf Nodes.

Now the only thing left is to traverse recursively to the last parent and check wether it has one child or 2 children and store the value of its child or sum of children into its info and if the children do not have any further children then set their value to 0.

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

struct BST
{
    struct BST* left;
    int info;
    struct BST* right;
};

struct BST* newNode(int);
void printTree(struct BST*);
void replaceParentWithSumOfChildren(struct BST*);