Fraktaali

import java.util.*;
/*
 * Datatähti 2018
 * Tuomas Karjalainen, Nurmeksen lukio
 */
public class Fraktaali {
  public static void main(String[] args) {
    Scanner input = new Scanner(System.in);
    final int maxK = Integer.parseInt(input.nextLine());
    final int gridSize = gridSizeAtK(maxK);
    boolean[][] grid = new boolean[gridSize][gridSize];
    grid[0][0] = true;

    for (int k=1; k < maxK; k++) {
      grid = stepFractal(grid, k);
    }

    printGrid(grid);
  }

  private static boolean[][] stepFractal(boolean[][] grid, int startK) {
    int startSize = gridSizeAtK(startK);
    // Clone right
    for (int y=0; y<startSize; y++) {
      for (int x=0; x<startSize; x++) {
        grid[startSize + x][y] = grid[x][y];
      }
    }
    // Clone down
    for (int y=0; y<startSize; y++) {
      for (int x=0; x<startSize; x++) {
        grid[x][startSize + y] = grid[x][y];
      }
    }
    // Clone south-east
    for (int y=0; y<startSize; y++) {
      for (int x=0; x<startSize; x++) {
        grid[startSize + x][startSize + y] = !grid[x][y];
      }
    }
    return grid;
  }

  private static int gridSizeAtK(int k) {
    int s = 1;
    while (k-- > 1) {
      s *= 2;
    }
    return s;
  }

  private static void printGrid(boolean[][] grid) {
    for (int y=0; y < grid.length; y++) {
      for (int x=0; x < grid.length; x++) {
        System.out.print(grid[x][y] ? '#' : '.');
      }
      System.out.println();
    }
  }
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 2

Verdict: ACCEPTED

Test 3

Group: 3

Verdict: ACCEPTED

Test 4

Group: 4

Verdict: ACCEPTED

Test 5

Group: 5

Verdict: ACCEPTED

Test 6

Group: 6

Verdict: ACCEPTED

Test 7

Group: 7

Verdict: ACCEPTED

Test 8

Group: 8

Verdict: ACCEPTED

Test 9

Group: 9

Verdict: ACCEPTED

Test 10

Group: 10

Verdict: ACCEPTED