Template: Answer on Binary Search

reference

PSUDO CODE-
-------------
int check(a,mid)
{
	// find answer using this mid
}
while(l<r)
{
	m = (l+r)/2;
	if(check(arr,m)>=givenK)
	//	move left or right accordingly
	else
	//	move left or right accordingly
} 
return ans;