CareerCup

#include <stdio.h>
#include <string.h>
struct tree *newnode(int data);
void push(int **data);
struct list
{
int data;
struct list *next;
}*top, *currentlevel=NULL,*nextlevel=NULL;
struct tree
{
int data;
struct tree *left;
struct tree *right;
};

main()
{
struct tree *tree1=newnode(1);
tree1->left=newnode(2);
tree1->right=newnode(3);
tree1->left->left=newnode(4);
tree1->left->right=newnode(5);
tree1->right->left=newnode(6);
tree1->right->right=newnode(7);
tree1->left->left->left=newnode(8);
tree1->left->left->right=newnode(9);
tree1->left->right->left=newnode(10);
tree1->left->right->right=newnode(11);
tree1->right->left->left=newnode(12);
tree1->right->left->right=newnode(13);
tree1->right->right->left=newnode(14);
tree1->right->right->right=newnode(15);
zigzag(tree1);
}
int zigzag(struct list *tree1)
{
int lefttoright=1;
push(tree1);
while(!isEmpty())
{
struct tree *tree3=pop();
printf(" %d",tree3->data);
if(lefttoright)
{
if(tree3->left!=0)
{
push1(tree3->left);
}
if(tree3->right!=0)
{
push1(tree3->right);
}
}
else
{
if(tree3->right!=0)
{
push1(tree3->right);
}
if(tree3->left!=0)
{
push1(tree3->left);
}
}
while(isEmpty())
{
lefttoright=1-lefttoright;
swap();
}
}
}
void swap()
{
currentlevel=nextlevel;
nextlevel=NULL;
}
int pop()
{
struct list *ptr;
ptr=currentlevel->data;
if(currentlevel==NULL)
{
printf(" overflow ");
}
currentlevel=currentlevel->next;
return ptr;
}
int isEmpty()
{
if(currentlevel==NULL)
{
return 1;
}
else
{
return 0;
}
}
struct tree *newnode(int data)
{
struct tree *tree3;
tree3=(struct tree *)malloc(sizeof(struct tree));
tree3->data=data;
tree3->left=NULL;
tree3->right=NULL;
return tree3;
}
void push(int **data)
{
struct list *p1=(struct list *)malloc(sizeof(struct list));
p1->data=data;
if(currentlevel==NULL)
{
p1->next=NULL;
currentlevel=p1;
}
else
{
p1->next=currentlevel;
currentlevel=p1;
}
}
void push1(int **data)
{
struct list *p11=(struct list *)malloc(sizeof(struct list));
p11->data=data;
if(nextlevel==NULL)
{
p11->next=NULL;
nextlevel=p11;
}
else
{
p11->next=nextlevel;
nextlevel=p11;
}
}