From f223efe9191ea8d6103c47d708b39f90d79e047f Mon Sep 17 00:00:00 2001
From: Stefan Katzensteiner <stefan.katzensteiner@mailbox.org>
Date: Thu, 18 Jul 2024 07:01:30 +0200
Subject: [PATCH] VRP complete enumeration assignment part

---
 .../m12s/vrp/VehicleRoutingProblem.java       | 56 +++++++++++++++----
 .../m12s/vrp/VehicleRoutingProblemTest.java   | 20 +++++++
 2 files changed, 66 insertions(+), 10 deletions(-)

diff --git a/src/main/java/io/gocklkatz/m12s/vrp/VehicleRoutingProblem.java b/src/main/java/io/gocklkatz/m12s/vrp/VehicleRoutingProblem.java
index fd63781..e83cc63 100644
--- a/src/main/java/io/gocklkatz/m12s/vrp/VehicleRoutingProblem.java
+++ b/src/main/java/io/gocklkatz/m12s/vrp/VehicleRoutingProblem.java
@@ -15,16 +15,52 @@ public VehicleRoutingProblem(List<List<Integer>> distanceMatrix) {
 
     public Solution solveCompleteEnumeration(){
 
-        /*
-           Assignment Problem
-             1) All combinations of 011100,100011
-               - All possible x = 000000 to 111111 and complement binary 111111 - x except 000000 and 111111
-             2) The power set and its complement
-           Routing Problem
-             All permutations of 3,4,5 and 1,2,6
-         */
-
-        return new Solution(new ArrayList<>(), new ArrayList<>());
+        Solution bestSolution = new Solution(new ArrayList<>(), new ArrayList<>());
+        bestSolution.setObjectiveFunctionValue(Double.MAX_VALUE);
+
+        int length = 6;
+        int numberOfElements = (int) Math.pow(2,length);
+        for(int i=1; i<numberOfElements-1; i++) {
+            //TODO The "convert to binary" parts are awfully similar
+            String unpaddedBinaryString1 = Integer.toBinaryString(i);
+            String paddedBinaryString1 = String.
+                    format("%1$" + length + "s", unpaddedBinaryString1).
+                    replace(' ', '0');
+
+            List<Integer> route1 = generateTour(paddedBinaryString1);
+
+            int j = numberOfElements - i - 1;
+            String unpaddedBinaryString2 = Integer.toBinaryString(j);
+            String paddedBinaryString2 = String.
+                    format("%1$" + length + "s", unpaddedBinaryString2).
+                    replace(' ', '0');
+
+            List<Integer> route2 = generateTour(paddedBinaryString2);
+
+            //TODO All permutation for route2 for each permutation of route1
+
+            Solution solution = new Solution(route1, route2);
+            solution.setObjectiveFunctionValue(calcZf(solution));
+
+            if(solution.getObjectiveFunctionValue() < bestSolution.getObjectiveFunctionValue()) {
+                bestSolution = solution;
+            }
+        }
+
+        return bestSolution;
+    }
+
+    private static List<Integer> generateTour(String assignment) {
+        List<Integer> tour = new ArrayList<>();
+
+        for(int i=assignment.length()-1; i>=0; i--) {
+            int active = Integer.parseInt(assignment.substring(i,i+1));
+            if(active == 1) {
+                tour.add(assignment.length()-i);
+            }
+        }
+
+        return tour;
     }
 
     public Solution singleSolution() {
diff --git a/src/test/java/io/gocklkatz/m12s/vrp/VehicleRoutingProblemTest.java b/src/test/java/io/gocklkatz/m12s/vrp/VehicleRoutingProblemTest.java
index 42719b9..1c6ae22 100644
--- a/src/test/java/io/gocklkatz/m12s/vrp/VehicleRoutingProblemTest.java
+++ b/src/test/java/io/gocklkatz/m12s/vrp/VehicleRoutingProblemTest.java
@@ -26,4 +26,24 @@ void givenCertainMatrix_whenCallingSingleSolution_shouldGiveKnownAnswer() {
 
         assertEquals(solution.getObjectiveFunctionValue(), 163);
     }
+
+    @Test
+    void givenCertainMatrix_whenCallingSolveCompleteEnumeration_shouldGiveKnownAnswer() {
+        //https://www.youtube.com/watch?v=A1wsIFDKqBk&t=362s
+        List<List<Integer>> matrix = new ArrayList<>();
+        matrix.add(List.of(0,  20, 18, 14, 16, 12, 19));
+        matrix.add(List.of(20,  0, 22, 18, 30, 26, 28));
+        matrix.add(List.of(18, 22,  0, 32, 20, 22, 21));
+        matrix.add(List.of(14, 18, 32,  0, 20, 22, 21));
+        matrix.add(List.of(16, 30, 20, 20,  0, 30, 22));
+        matrix.add(List.of(12, 26, 22, 22, 30,  0, 26));
+        matrix.add(List.of(19, 28, 21, 21, 22, 26,  0));
+
+        VehicleRoutingProblem vrp = new VehicleRoutingProblem(matrix);
+        Solution solution = vrp.solveCompleteEnumeration();
+
+        assertEquals(List.of(2, 5), solution.getRoute1());
+        assertEquals(List.of(1, 3, 4, 6), solution.getRoute2());
+        assertEquals(solution.getObjectiveFunctionValue(), 151);
+    }
 }
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