Лабораторная работа №32

Author: EgorBurov246

students/23K0815/23K0815-p32/src/main/java/ru/mirea/practice/s0000001/task1/JohnsonTrotter.java

@@ -0,0 +1,82 @@
+package ru.mirea.practice.s0000001.task1;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public final class PermutationGenerator {
+
+    private PermutationGenerator() {
+        // Prevent instantiation
+    }
+
+    static class Item {
+        int number;
+        boolean isMovingRight;
+
+        Item(int number) {
+            this.number = number;
+            this.isMovingRight = false; // Initially set to move left
+        }
+    }
+
+    public static void main(String[] args) {
+        int count = 10;  // Changed from 4 to 10
+        createPermutations(count);
+    }
+
+    public static void createPermutations(int count) {
+        List<Item> items = new ArrayList<>();
+        for (int i = 1; i <= count; i++) {
+            items.add(new Item(i));
+        }
+
+        displayPermutation(items);
+
+        while (true) {
+            int indexOfLargestMovable = findLargestMovable(items);
+            if (indexOfLargestMovable == -1) {
+                break;
+            }
+
+            Item largestItem = items.get(indexOfLargestMovable);
+            int targetIndex = largestItem.isMovingRight ? indexOfLargestMovable + 1 : indexOfLargestMovable - 1;
+            swapItems(items, indexOfLargestMovable, targetIndex);
+
+            for (Item item : items) {
+                if (item.number > largestItem.number) {
+                    item.isMovingRight = !item.isMovingRight; // Change direction
+                }
+            }
+
+            displayPermutation(items);
+        }
+    }
+
+    private static int findLargestMovable(List<Item> items) {
+        int movableIndex = -1;
+        for (int i = 0; i < items.size(); i++) {
+            Item currentItem = items.get(i);
+            int neighborIndex = currentItem.isMovingRight ? i + 1 : i - 1;
+
+            if (neighborIndex >= 0 && neighborIndex < items.size() && currentItem.number > items.get(neighborIndex).number) {
+                if (movableIndex == -1 || currentItem.number > items.get(movableIndex).number) {
+                    movableIndex = i;
+                }
+            }
+        }
+        return movableIndex;
+    }
+
+    private static void swapItems(List<Item> items, int firstIndex, int secondIndex) {
+        Item temp = items.get(firstIndex);
+        items.set(firstIndex, items.get(secondIndex));
+        items.set(secondIndex, temp);
+    }
+
+    private static void displayPermutation(List<Item> items) {
+        for (Item item : items) {
+            System.out.print(item.number + " ");
+        }
+        System.out.println();
+    }
+}