#include<stdio.h>
#include<malloc.h>
struct binaryTreeNode{
int data;
struct binaryTreeNode * left;
struct binaryTreeNode * right;
};
struct node
{
struct binaryTreeNode * data;
struct node * next;
};
struct queue
{
struct node * front;
struct node * rear;
};
struct queue * enQueue(struct queue * q, struct binaryTreeNode * num)
{
struct node
* temp
= (struct node
*)malloc(sizeof(struct node
)); temp -> data = num;
temp -> next = NULL;
if(q == NULL)
{
q
= (struct queue
*)malloc(sizeof(struct queue
)); q -> front = temp;
}
else
q -> rear -> next = temp;
q -> rear = temp;
//Code obtained from http://w...content-available-to-author-only...s.com
//Feel free to copy but please acknowledge the site wherever possible
return q;
}
struct queue * deQueue(struct queue * q)
{
struct node * temp = q->front;
q -> front = q->front->next;
if(q->front == NULL)
return NULL;
else
return q;
}
int isQueueEmpty(struct queue * q)
{
if(q)
return 0;
else
return 1;
}
int numberOfLeaves(struct binaryTreeNode * root)
{
// Level order traversal
struct binaryTreeNode * temp = NULL;
struct queue * Q = NULL;
// Maintain a count
int count = 0;
if(root == NULL)
return 0;
Q = enQueue(Q, root);
while(!isQueueEmpty(Q))
{
temp = Q -> front -> data;
// Now check if the node is a leaf node
if(temp -> left == NULL && temp -> right == NULL)
{
// This means a leaf node
count++;
}
Q = deQueue(Q);
if(temp -> left)
Q = enQueue(Q, temp -> left);
if(temp -> right)
Q = enQueue(Q, temp -> right);
}
// Delete the queue
// Now return the count
return count;
}
// Test the above functions
int main(void)
{
// Initialize the tree
struct binaryTreeNode
* root
= (struct binaryTreeNode
*)malloc(sizeof(struct binaryTreeNode
)); root-> data = 1;
struct binaryTreeNode
* l
= (struct binaryTreeNode
*)malloc(sizeof(struct binaryTreeNode
)); l -> data = 2;
struct binaryTreeNode
* ll
= (struct binaryTreeNode
*)malloc(sizeof(struct binaryTreeNode
)); ll -> data = 4;
ll -> left = ll -> right = NULL;
struct binaryTreeNode
* lr
= (struct binaryTreeNode
*)malloc(sizeof(struct binaryTreeNode
)); lr -> data = 5;
lr -> left = lr -> right = NULL;
l -> left = ll;
l -> right = lr;
struct binaryTreeNode
* r
= (struct binaryTreeNode
*)malloc(sizeof(struct binaryTreeNode
)); r -> data = 3;
struct binaryTreeNode
* rl
= (struct binaryTreeNode
*)malloc(sizeof(struct binaryTreeNode
)); rl -> data = 6;
rl -> left = rl -> right = NULL;
struct binaryTreeNode
* rr
= (struct binaryTreeNode
*)malloc(sizeof(struct binaryTreeNode
)); rr -> data = 7;
rr -> left = rr -> right = NULL;
r -> left = rl;
r -> right = rr;
root -> left = l;
root -> right = r;
printf("Number of leaf nodes = %d",numberOfLeaves
(root
));
return 0;
}