'#15.'Optimize slicing algoritm, avoiding iterations thru finished start positions

Author: seajer

src/main/java/com/google/hashcode/App.java

@@ -11,6 +11,7 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 
@@ -30,18 +31,18 @@ public static void main(String[] args) throws IOException {
 
     public static void slicePizza(String inputFile, String outputFile) throws IOException {
         Profiler profiler = new Profiler();
-        List<Slice> output;
+        List<Slice> startPositions;
+        List<Slice> output = new ArrayList<>();
         Pizza pizza = new Pizza(new File(inputFile), IoUtils.parsePizza(inputFile), IoUtils.parseSliceInstructions(inputFile));
         //get start positions
-        output = DFSMethods.cutAllStartPositions(pizza);
+        startPositions = DFSMethods.cutAllStartPositions(pizza);
         //get All steps
-        Map<Slice, List<Step>> availableSteps = DFSMethods.getAvailableSteps(pizza, output);
+        Map<Slice, List<Step>> availableSteps = DFSMethods.getAvailableSteps(pizza, startPositions, output);
         while (!availableSteps.values().stream().allMatch(List::isEmpty)) {
             Step step = DFSMethods.selectStep(availableSteps);
-            output.remove(step.startPosition);
-            output.add(DFSMethods.performStep(pizza, step));
+            DFSMethods.performStep(pizza, step, startPositions, output);
             //TODO available steps should include merging slices to each other
-            availableSteps = DFSMethods.getAvailableSteps(pizza, output);
+            availableSteps = DFSMethods.getAvailableSteps(pizza, startPositions, output);
             LOGGER.info("OUTPUT AFTER A STEP: "
                     + "\n " + output);
         }

src/main/java/com/google/hashcode/entity/Cell.java

@@ -28,9 +28,9 @@ public boolean equals(Object o) {
         if (this == o) return true;
         if (!(o instanceof Cell)) return false;
         Cell cell = (Cell) o;
-        return x == cell.x &&
-                y == cell.y &&
-                ingredient == cell.ingredient;
+        return this.x == cell.x &&
+                this.y == cell.y &&
+                this.ingredient == cell.ingredient;
     }
 
     @Override

src/main/java/com/google/hashcode/utils/DFSMethods.java

@@ -19,9 +19,10 @@ private DFSMethods() {
      * remove this slice from startPositions and add all it's cells to pizza.
      * @param pizza          given pizza
      * @param startPositions given slices in the pizza
+     * @param output
      * @return available steps
      */
-    public static Map<Slice, List<Step>> getAvailableSteps(Pizza pizza, List<Slice> startPositions) {
+    public static Map<Slice, List<Step>> getAvailableSteps(Pizza pizza, List<Slice> startPositions, List<Slice> output) {
         Map<Slice, List<Step>> groupedSteps = new HashMap<>();
         Iterator iter = startPositions.iterator();
         while (iter.hasNext()) {
@@ -43,7 +44,8 @@ public static Map<Slice, List<Step>> getAvailableSteps(Pizza pizza, List<Slice>
                 if (startPosition.isValid(pizza)) {
                     // if slice is valid and have'nt any steps -> cut it from
                     // startPositions
-                    groupedSteps.put(startPosition, steps);
+                    output.add(startPosition);
+                    iter.remove();
                 } else {
                     // if slice isn't valid and have'nt any steps -> return all
                     // it cells to pizza
@@ -66,20 +68,32 @@ public static Map<Slice, List<Step>> getAvailableSteps(Pizza pizza, List<Slice>
      *
      * @param pizza given pizza
      * @param step  step to perform
-     * @return formed slice that includes an original slice and delta from a step
+     * @param startPositions
+     *@param output @return formed slice that includes an original slice and delta from a step
      */
-    public static Slice performStep(Pizza pizza, Step step) {
+    public static void performStep(Pizza pizza, Step step, List<Slice> startPositions, List<Slice> output) {
         //1. Pick ups a steps list with minimal total cells number
         LOGGER.info("STEP TO PERFORM " + step);
         //2. Cut all the step delta cells from pizza
         LOGGER.info("pizza before step: " + pizza
                 + "\ndelta to remove from the pizza: " + step.delta);
         pizza.getCells().removeAll(step.delta.cells);
+
+        //3. remove previous version start position from startPositions
+        startPositions.remove(step.startPosition);
+
+        List<Cell> returnedList = step.startPosition.cells;
+        returnedList.addAll(step.delta.cells);
+        Slice finalSlice = new Slice(returnedList);
+
         LOGGER.info("PIZZA AFTER STEP:" + pizza);
         //3. Add the step cells to an output slice
-        Slice slice = new Slice(step.delta.cells);
-        slice.cells.addAll(step.startPosition.cells);
-        return slice;
+
+        if(finalSlice.cells.size() == pizza.getSliceInstruction().getMaxNumberOfCellsPerSlice()){
+            output.add(finalSlice);
+        } else{
+            startPositions.add(finalSlice);
+        }
     }
 
     /**

src/test/java/com/google/hashcode/utils/DFSMethodsTest.java

@@ -6,6 +6,7 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
@@ -27,7 +28,8 @@ public void setup() throws IOException {
 
     @Test
     public void getAvailableSteps() throws IOException {
-        Map<Slice, List<Step>> actualMap = DFSMethods.getAvailableSteps(pizza, DFSMethods.cutAllStartPositions(pizza));
+        List<Slice> output = new ArrayList<>();
+        Map<Slice, List<Step>> actualMap = DFSMethods.getAvailableSteps(pizza, DFSMethods.cutAllStartPositions(pizza), output);
         assertEquals(3, actualMap.keySet().size());
         assertEquals(3, actualMap.get(new Slice(new Cell(1, 1, Ingredient.MUSHROOM))).size());
         assertEquals(2, actualMap.get(new Slice(new Cell(1, 2, Ingredient.MUSHROOM))).size());
@@ -47,10 +49,12 @@ public void cutAllStartPositions() throws IOException {
 
     @Test
     public void performStep() {
-        List<Slice> output = DFSMethods.cutAllStartPositions(pizza);
-        Map<Slice, List<Step>> availableSteps = DFSMethods.getAvailableSteps(pizza, output);
-        Slice slice = DFSMethods.performStep(pizza, DFSMethods.selectStep(availableSteps));
-        assertEquals(new Slice(Arrays.asList(new Cell(2, 2, Ingredient.TOMATO), new Cell(1, 2, Ingredient.MUSHROOM))), slice);
+        List<Slice> startPositions = DFSMethods.cutAllStartPositions(pizza);
+        List<Slice> output = new ArrayList<>();
+        Map<Slice, List<Step>> availableSteps = DFSMethods.getAvailableSteps(pizza, startPositions, output);
+        DFSMethods.performStep(pizza, DFSMethods.selectStep(availableSteps), startPositions, output);
+        assertEquals(new Slice(Arrays.asList(new Cell(1, 2, Ingredient.MUSHROOM), new Cell(2, 2, Ingredient.TOMATO)))
+                , startPositions.get(2));
         assertEquals(11, pizza.getCells().size());
     }
 }