Time complexity of min coin change

how it is O(NT) in both the approach

IN BOTTOM UP APPROACH

There is two nested loop in the code. The first loop is iterating from 1 to n and the second is iterating from 1 to T. Time Complexity = O(A*m ) , where T is the number of coins

what about top down approach

similarly in top down
your recursive function run n times and in each function call loop runs T time
hence time Complexity will be O(NT)