1 |
1 import scala.util._ |
2 |
2 |
3 def print_board(n: Int)(steps: List[(Int, Int)]): Unit = { |
3 def print_board(n: Int)(steps: List[(Int, Int)]): Unit = { |
4 for (i <- 0 until n) { |
4 for (i <- 0 until n) { |
5 for (j <- 0 until n) { |
5 for (j <- 0 until n) { |
6 print(f"${steps.indexOf((i, j))}%2.0f ") |
6 print(f"${steps.indexOf((i, j))}%3.0f ") |
7 } |
7 } |
8 println |
8 println |
9 } |
9 } |
10 //readLine() |
10 //readLine() |
11 System.exit(0) |
11 //System.exit(0) |
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12 throw new Exception("\n") |
12 } |
13 } |
13 |
14 |
14 def add_pair(x: (Int, Int))(y: (Int, Int)) = |
15 def add_pair(x: (Int, Int))(y: (Int, Int)) = |
15 (x._1 + y._1, x._2 + y._2) |
16 (x._1 + y._1, x._2 + y._2) |
16 |
17 |
20 def moves(n: Int)(x: (Int, Int)): List[(Int, Int)] = { |
21 def moves(n: Int)(x: (Int, Int)): List[(Int, Int)] = { |
21 List((1, 2),(2, 1),(2, -1),(1, -2), |
22 List((1, 2),(2, 1),(2, -1),(1, -2), |
22 (-1, -2),(-2, -1),(-2, 1),(-1, 2)).map(add_pair(x)).filter(is_legal(n)) |
23 (-1, -2),(-2, -1),(-2, 1),(-1, 2)).map(add_pair(x)).filter(is_legal(n)) |
23 } |
24 } |
24 |
25 |
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26 def ordered_moves(n: Int)(steps: List[(Int, Int)])(x : (Int, Int)): List[(Int, Int)] = |
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27 moves(n)(x).sortBy((x: (Int, Int)) => moves(n)(x).filterNot(steps.contains(_)).length) |
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28 |
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29 moves(8)(1,3) |
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30 ordered_moves(8)(Nil)(1,3) |
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31 ordered_moves(8)(List((2, 4), (2, 6)))(1,3) |
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32 |
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33 // non-circle tour parallel |
25 def tour(n: Int)(steps: List[(Int, Int)]): Unit = { |
34 def tour(n: Int)(steps: List[(Int, Int)]): Unit = { |
26 if (steps.length == n * n && moves(n)(steps.head).contains(steps.last)) |
35 if (steps.length == n * n) |
27 print_board(n)(steps) |
36 print_board(n)(steps) |
28 else |
37 else |
29 for (x <- moves(n)(steps.head); if (!steps.contains(x))) tour(n)(x :: steps) |
38 for (x <- moves(n)(steps.head); if (!steps.contains(x))) tour(n)(x :: steps) |
30 } |
39 } |
31 |
40 |
32 val n = 6 |
41 // non-circle tour |
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42 def ctour(n: Int)(steps: List[(Int, Int)]): Unit = { |
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43 if (steps.length == n * n && moves(n)(steps.head).contains(steps.last)) |
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44 print_board(n)(steps) |
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45 else |
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46 for (x <- moves(n)(steps.head).par; if (!steps.contains(x))) ctour(n)(x :: steps) |
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47 } |
33 |
48 |
34 println("started") |
49 |
35 for (i <- 0 until n; j <- 0 until n) tour(n)(List((i, j))) |
50 def faster_tour(n: Int)(steps: List[(Int, Int)]): Unit = { |
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51 if (steps.length == n * n && moves(n)(steps.head).contains(steps.last)) |
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52 print_board(n)(steps) |
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53 else |
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54 for (x <- ordered_moves(n)(steps)(steps.head).par; if (!steps.contains(x))) faster_tour(n)(x :: steps) |
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55 } |
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56 |
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57 |
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58 val n1 = 5 |
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59 println(s"simple tour: n = $n1") |
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60 |
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61 Try { |
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62 for (i <- 0 until n1; j <- 0 until n1) { |
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63 tour(n1)(List((i, j))) |
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64 } |
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65 } |
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66 |
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67 |
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68 /* |
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69 val n2 = 6 |
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70 println(s"circle tour: n = $n2") |
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71 |
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72 Try { |
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73 for (i <- 0 until n2; j <- 0 until n2) { |
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74 ctour(n2)(List((i, j))) |
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75 } |
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76 } |
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77 */ |
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78 |
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79 val n3 = 9 |
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80 println(s"fast circle tour: n = $n3") |
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81 |
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82 Try { |
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83 for (i <- 0 until n3; j <- 0 until n3) { |
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84 faster_tour(n3)(List((i, j))) |
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85 } |
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86 } |
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87 |
36 println("finished") |
88 println("finished") |