Cleaned up the code and improved report

diff --git a/LubbersReport.tex b/LubbersReport.tex
index e175b99..ceaa068 100644 (file)
--- a/LubbersReport.tex
+++ b/LubbersReport.tex
@@ -45,8 +45,8 @@
 \end{center}
 
 The assignment is to implement a \textit{\href{http://www.java.com}{Java}}
-program that optimizes the assignment of pets to children so that the sum of
-all the compatibility values between pets and children is the maximum possible.
+program that maximizes the sum of the compatibiliy values of the pet-child
+combination.
 
 \section{Implementation}
 \subsection{Brute Force}
@@ -55,15 +55,13 @@ every possible combination of pets and children and then takes the one with the
 highest value. This corresponds with the pseudocode specified together with a
 rough estimate of the complexity in Listing~\ref{lst:brute_force}. The
 algorithm, due to calculating all the values the algorithm has a complexity
-within $\mathcal{O}(n!)$.
-This is because there are $n!$ permutations possible for $n$ children.
-\begin{lstlisting}[
-       caption={Brute Force approach},
-       label={lst:brute_force},
-       keywords={[3]loop,put,return}
-]
+within $\mathcal{O}(n!)$. This is because there are $n!$ permutations possible for $n$ children.
+Because of the rapid growth due to the complexity level the algorithm doesn't
+scale up well.
+\begin{lstlisting}[caption={Brute Force approach}, label={lst:brute_force},
+                   keywords={[3]loop,put,return}]
 n! - loop over all permutations
-c1 -   put compatibility in list
+n  -   put compatibility in list
 c1 - return maximum compatibility rating from list
 \end{lstlisting}
 
@@ -76,10 +74,8 @@ estimate of the complexity in Listing~\ref{lst:improved}. The algorithm has a
 complexity lies in the $\mathcal{O}(nm)$ because the main loop repeats at
 maximum $n$ or $m$ times and the searching within the loop has a complexity of
 $n$ if the loop runs $m$ times and $m$ otherwise. 
-\begin{lstlisting}[
-       caption={Improved approach},
-       label={lst:improved},
-       keywords={[3]while,create,put,return,find,remove}
+\begin{lstlisting}[caption={Improved approach}, label={lst:improved},
+                    keywords={[3]while,create,put,return,find,remove}
 ]
 n         - create list result of length n and initialize with -1
 n+m       - create list rows/columns that contain pairs of indices and sums of values

diff --git a/LubbersSolver.java b/LubbersSolver.java
index 8a280b0..7ae5a0d 100755 (executable)
--- a/LubbersSolver.java
+++ b/LubbersSolver.java
@@ -29,10 +29,10 @@ public class LubbersSolver implements IPetproblemSolver {
                        }
                        rows.add(new SimpleEntry<Integer, Integer>(i, sum));
                }
-               for (int i = 0; i < m; i++) {
+               for (int i = 0; i < m; i++)
                        cols.add(new SimpleEntry<Integer, Integer>(i, col_sums[i]));
-               }
-               //Sort the lists so the rows and columns with the least amount of positive compatibilities 
+
+               //Sort the lists so the rows and columns with the least amount of positive compatibilities are up front
                Comparator<SimpleEntry<Integer, Integer>> comp = new Comparator<SimpleEntry<Integer, Integer>>() {
                        @Override
                        public int compare(SimpleEntry<Integer, Integer> a, SimpleEntry<Integer, Integer> b) {
@@ -47,7 +47,6 @@ public class LubbersSolver implements IPetproblemSolver {
                 * 2. Find the match with the lowest sum and still positive compatibility for that row or column
                 * 3. Select smallest from those indices
                 */
-               SimpleEntry<Integer, Integer> MINIMUM = new SimpleEntry<Integer, Integer>(-1, Integer.MAX_VALUE);
                while (!(rows.isEmpty() || cols.isEmpty())) {
                        //1. Find the row or column with the lowest sum(least available matches)
                        SimpleEntry<Integer, Integer> row_l = rows.peekFirst();
@@ -58,35 +57,29 @@ public class LubbersSolver implements IPetproblemSolver {
                                //Remove the current lowest row sum
                                rows.remove(row_l);
                                //3. Find smallest column that has compatibility 1
-                               SimpleEntry<Integer, Integer> smallest = MINIMUM;
-                               for (SimpleEntry<Integer, Integer> e : cols) {
-                                       if (e.getValue() < smallest.getValue() && compatibility[row_l.getKey()][e.getKey()] == 1) {
-                                               smallest = e;
-                                       }
-                               }
+                               SimpleEntry<Integer, Integer> min = new SimpleEntry<Integer, Integer>(-1, Integer.MAX_VALUE);
+                               for (SimpleEntry<Integer, Integer> e : cols)
+                                       if (e.getValue() < min.getValue() && compatibility[row_l.getKey()][e.getKey()] == 1)
+                                               min = e;
                                //No pets left that have a positive compatibility
-                               if (smallest.getKey() == -1) {
-                                       continue;
+                               if (min.getKey() != -1) {
+                                       cols.remove(min);
+                                       result[row_l.getKey()] = min.getKey();
                                }
-                               cols.remove(smallest);
-                               result[row_l.getKey()] = smallest.getKey();
                        //2. The column is the lowest
                        } else {
                                //Remove the current lowest column sum
                                cols.remove(col_l);
                                //3. Find smallest row that has compatibility 1
-                               SimpleEntry<Integer, Integer> smallest = MINIMUM;
-                               for (SimpleEntry<Integer, Integer> e : rows) {
-                                       if (e.getValue() < smallest.getValue() && compatibility[e.getKey()][col_l.getKey()] == 1) {
-                                               smallest = e;
-                                       }
-                               }
-                               //No pets left that have a positive compatibility
-                               if (smallest.getKey() == -1) {
-                                       continue;
+                               SimpleEntry<Integer, Integer> min = new SimpleEntry<Integer, Integer>(-1, Integer.MAX_VALUE);
+                               for (SimpleEntry<Integer, Integer> e : rows)
+                                       if (e.getValue() < min.getValue() && compatibility[e.getKey()][col_l.getKey()] == 1)
+                                               min = e;
+                               //If there is a pet left, remove it and assign it
+                               if (min.getKey() != -1) {
+                                       rows.remove(min);
+                                       result[min.getKey()] = col_l.getKey();
                                }
-                               rows.remove(smallest);
-                               result[smallest.getKey()] = col_l.getKey();
                        }
                }
                return result;