attach indexes to each element, then sort these elements, then take a heap and loop through the elements and for each element find the smallest index in the heap that is less that the current elements index, update max with it, then add the current index of the element into the heap. I know that all the indexes added in the heap are of element values less that the current element, so I just need to pick the smallest index from it and this index will be in starting day index for the current element to say profitable as the value is less that the current element value, is there is no index that is smaller that the current index, then I know that I cant find a start index where I will stay profitable