#include<stdio.h>
#define MIN -65535
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...w.studyalgorithms,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 findMaxInTree(struct binaryTreeNode * root)
{
// A variable for root value
int root_val;
// Variable to store values in left and right tree
int left, right;
// Initialize it with a minimum value
int max = MIN;
if(root != NULL)
{
// Get the root value
root_val = root -> data;
// Find the maximum value in left sub-tree
left = findMaxInTree(root -> left);
// Find the maximum value in right sub-tree
right = findMaxInTree(root -> right);
// Now find the largest of 3 values
// Find which is big among left and right
if(left > right)
max = left;
else
max = right;
// Compare the max with root value
if(root_val > max)
max = root_val;
}
return max;
}
int findMaxInTreeNonRecursive(struct binaryTreeNode * root)
{
// Initialize max with a very less value;
int max = MIN;
// Level Order Traversal
struct binaryTreeNode * temp = NULL;
struct queue * Q = NULL;
if(root == NULL)
return;
Q = enQueue(Q, root);
while(!isQueueEmpty(Q))
{
temp = Q -> front -> data;
Q = deQueue(Q);
// Find the max value
if(temp -> data > max)
max = temp -> data;
if(temp -> left)
Q = enQueue(Q, temp -> left);
if(temp -> right)
Q = enQueue(Q, temp -> right);
}
return max;
}
// 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;
// Non-recursive version
printf("max = %d",findMaxInTree
(root
));
// Recursive version
printf("max = %d",findMaxInTreeNonRecursive
(root
));
return 0;
}