Recursion needs to be used. Assume it is filled with infinte values, so the first element to add should be at the top left of the matrix and since inf is highest value you won't have to do anything, but when you add another element you have to rearrange. you have to figure out where to put the element and how to rearrange. $($bubble up smallest element$)$ this problem is similar to a max heap but instead it uses the smallest elements so think of that when solving the problem. thank you.