Consider a single linked list with 'n' nodes and other single linked list with 'm' nodes

At the 'k'th node in 'n' ,the second linked list merges at some part of it .. jst like the shape Y

Now i was asked to find out the address of Kth node

I did it by taking the address of the each node in an array and compared with the address of the 2nd linked list with a time complexity of O(n*m)

But i was asked to reduce the time complexity .. even assuming that 'n' and 'm' are equal

Is there any possible method to reduce the time complexity other than O(n*n) ??