Given an array of positive numbers, find sub-sequence of length three having maximum product. The elements of sub-sequence should be in increasing order. For example, for the input array {8, 9, 5, 1, 10, 3, 12} output should be sub-sequence 9, 10, 12. For the input array {6, 1, 2, 3, 19, 10, 7} output sub-sequence should be 2, 3, 19.