Friday, 30 September 2016

Binary Search Tree: Count number of Leaf nodes

Count number of leaf nodes in Binary Search Tree



#include<stdio.h>
#include<stdlib.h>
struct BST
{
            int data;
            struct BST *lchild;
            struct BST *rchild;
};
typedef struct BST * NODE;
int leaf=0;

NODE get_node()
{
            NODE temp;
            temp = (NODE) malloc(sizeof(struct BST));
            temp->lchild = NULL;
            temp->rchild = NULL;
            return temp;
}

void insert(NODE root, NODE newnode)
{
            if (newnode->data < root->data)
            {
                        if (root->lchild == NULL)
                                    root->lchild = newnode;
                        else
                                    insert(root->lchild, newnode);
            }
            if (newnode->data > root->data)
            {
                        if (root->rchild == NULL)
                                    root->rchild = newnode;
                        else
                                    insert(root->rchild, newnode);
            }
}

int leaf_nodes(NODE root)
{
            if(root == NULL)
                        return 0;
            if(root->lchild == NULL && root->rchild==NULL)
                        leaf++;
            leaf_nodes(root->lchild);
            leaf_nodes(root->rchild);
            return leaf;
}

void main()
{
            int val, i,n, ln;
            NODE root = NULL, newnode;
            printf("\nEnter the number of elements: ");
            scanf("%d",&n);
            for(i=1;i<=n;i++)
            {
                        newnode = get_node();
                        printf("\nEnter The node value: ");
                        scanf("%d", &val);
                        newnode->data = val;
                        if (root == NULL)
                                    root = newnode;
                        else
                                    insert(root, newnode);
            }

            ln = leaf_nodes(root);
            printf("\nTotal number of leaf nodes is: %d", ln);
}

Output:
Enter the number of elements: 12
Enter The node value: 6
Enter The node value: 9
Enter The node value: 5
Enter The node value: 2
Enter The node value: 8
Enter The node value: 15
Enter The node value: 24
Enter The node value: 14
Enter The node value: 7
Enter The node value: 8
Enter The node value: 5
Enter The node value: 2
Total number of leaf nodes is: 4