CareerCup

If we're dealing with a tree, just use a BFS and break on level k.

O(E+V)

Of course BFS :)

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

struct BT
{
struct BT *l;
struct BT *r;
int data;
};
void findKthnodes(struct BT *root,int level,int k)
{

if(!root)
return;
if()
if(level==k)
printf("[%d]\t",root->data);

findKthnodes(root->l, level+1,k);
findKthnodes(root->r,level+1,k);

}

struct BT *nn(int d)
{
struct BT *root=(struct BT *)malloc(sizeof(struct BT) );
root->l=NULL;
root->r=NULL;
root->data=d;
return root;
}

main()
{
struct BT *rt=nn(5);
rt->l=nn(45);
rt->r=nn(565);
rt->l->l=nn(453);
rt->l->r=nn(33);
rt->r->l=nn(656);
rt->r->r=nn(55);
rt->r->l->r=nn(56);

int level=0;
int k=2;
findKthnodes(root,level,k);


}