code: import java.util.*;
  
  public class HolyKnightsTour {
  
      final static String[] board = {
          " xxx    ",
          " x xx   ",
          " xxxxxxx",
          "xxx  x x",
          "x x  xxx",
          "1xxxxxx ",
          "  xx x  ",
          "   xxx  "};
  
      private final static int base = 12;
      private final static int[][] moves = {{1, -2}, {2, -1}, {2, 1}, {1, 2},
      {-1, 2}, {-2, 1}, {-2, -1}, {-1, -2}};
      private static int[][] grid;
      private static int total = 2;
  
      public static void main(String[] args) {
          int row = 0, col = 0;
  
          grid = new int[base][base];
  
          for (int r = 0; r < base; r++) {
              Arrays.fill(grid[r], -1);
              for (int c = 2; c < base - 2; c++) {
                  if (r >= 2 && r < base - 2) {
                      if (board[r - 2].charAt(c - 2) == 'x') {
                          grid[r][c] = 0;
                          total++;
                      }
                      if (board[r - 2].charAt(c - 2) == '1') {
                          row = r;
                          col = c;
                      }
                  }
              }
          }
  
          grid[row][col] = 1;
  
          if (solve(row, col, 2))
              printResult();
      }
  
      private static boolean solve(int r, int c, int count) {
          if (count == total)
              return true;
  
          List<int[]> nbrs = neighbors(r, c);
  
          if (nbrs.isEmpty() && count != total)
              return false;
  
          Collections.sort(nbrs, (a, b) -> a[2] - b[2]);
  
          for (int[] nb : nbrs) {
              r = nb[0];
              c = nb[1];
              grid[r][c] = count;
              if (solve(r, c, count + 1))
                  return true;
              grid[r][c] = 0;
          }
  
          return false;
      }
  
      private static List<int[]> neighbors(int r, int c) {
          List<int[]> nbrs = new ArrayList<>();
  
          for (int[] m : moves) {
              int x = m[0];
              int y = m[1];
              if (grid[r + y][c + x] == 0) {
                  int num = countNeighbors(r + y, c + x) - 1;
                  nbrs.add(new int[]{r + y, c + x, num});
              }
          }
          return nbrs;
      }
  
      private static int countNeighbors(int r, int c) {
          int num = 0;
          for (int[] m : moves)
              if (grid[r + m[1]][c + m[0]] == 0)
                  num++;
          return num;
      }
  
      private static void printResult() {
          for (int[] row : grid) {
              for (int i : row) {
                  if (i == -1)
                      System.out.printf("%2s ", ' ');
                  else
                      System.out.printf("%2d ", i);
              }
              System.out.println();
          }
      }
  }
  