a) Complete the Java code below so that the method outputs all digit strings, 1 n 10, in which the digits appear in strictly increasing order. For example, if n = 2, the programs output would include: 01, 02, ..., 09, 12, 13, ..., 19, 23, 24, ..., 29, 34, 35, ..., 39, 45, 46, ...., 49, 56, 57, 58, 59, 67, 68, 69, 78, 79, 89.

static void increasingStrings(int n) {

}

note: use call a recursive helper function for either or both of these problems.

b) How many strings are printed by your algorithm? Hint: Think about the combinatorial objects that you studied in Discrete Math.