CS331 Advanced Data Structures – Spring 2016 Homework 1 – 50 points Due: Feb. 1 1. (10 points) (a) Determine the number of inversions of the sequence 5,3,9,2,1,0,8,4,6,7 with respect to the sequence 0, 1, 2, . . . 9 (b) What would be the last number of inversions returned from our modified merge function discussed in class? (c) Assume we have a list of n items. Determine a relationship between the number of inversions with respect to the ascending sorted list and the number of inversions with respect to the descending sorted list. 2. (20 points) You are a real estate broker who has a square section of land you wish to sell. The land is divided up into square sections, and you are selling them in groups of three, in the following shape: There is only one problem: one of the squares of land has been designated as wetlands, and it is illegal for you or anyone else to build on it. Thus this square cannot be a part of any of the 3-square parcels you are selling. Given the location of this wetland square, you would like to find a way to divide the land into the 3-square parcels. For example, if the wetland square is the x-ed out square in the first figure below, then one possible division of the land is shown on the right: @ @ @ @ Write a divide-and-conquer algorithm to solve this following problem. The input will consist of three numbers: n (the side length of the square land to divide, always a power of 2), r and c (the coordinates of wetlands square, each in the range 0 . . . n − 1). Given this, you should output the grid with numbers indicating which squares are included in each of the 3-parcel tracts of land. One possible output for the above example might be: 2 -1 2 2 3 1 3 3 4 1 1 5 4 4 5 5 PROGRAM HINT: Divide the parcel into 4 even size sections and determine which section the wetlands square is, i.e. a square that should not be used. Then place a 3-parcel piece on the grid in such a way that EACH of the 4 smaller sections now has a square that should not be used. (over) 3. (20 points) Write a backtracking program to read in and solve a crypto-arithmetic problem. Input will be an integer n indicating the number of addends, followed by the n addends and then the crypto-arithmetic problem, or indicate that there are no solutions. For example, the input 2 SEND MORE MONEY corresponds to the crypto-arithmetic problem SEND + MORE MONEY Your solutions should look something like Solution 1: 9567 +1085 ----10652 On input 3 A A A B your solutions should look something like Solution 1: 1 +1 +1 +1 -4 Solution 2: 2 +2 +2 +2 -8 The maximum value for n will be 5, and each string will be no more than 10 letters long. More points will be given for a branch-and-bound solution as opposed to a straight backtracking solution.