RosettaCodeData/Task/Solve-a-Numbrix-puzzle/Java/solve-a-numbrix-puzzle.java

92 lines
2.5 KiB
Java

import java.util.*;
public class Numbrix {
final static String[] board = {
"00,00,00,00,00,00,00,00,00",
"00,00,46,45,00,55,74,00,00",
"00,38,00,00,43,00,00,78,00",
"00,35,00,00,00,00,00,71,00",
"00,00,33,00,00,00,59,00,00",
"00,17,00,00,00,00,00,67,00",
"00,18,00,00,11,00,00,64,00",
"00,00,24,21,00,01,02,00,00",
"00,00,00,00,00,00,00,00,00"};
final static int[][] moves = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
static int[][] grid;
static int[] clues;
static int totalToFill;
public static void main(String[] args) {
int nRows = board.length + 2;
int nCols = board[0].split(",").length + 2;
int startRow = 0, startCol = 0;
grid = new int[nRows][nCols];
totalToFill = (nRows - 2) * (nCols - 2);
List<Integer> lst = new ArrayList<>();
for (int r = 0; r < nRows; r++) {
Arrays.fill(grid[r], -1);
if (r >= 1 && r < nRows - 1) {
String[] row = board[r - 1].split(",");
for (int c = 1; c < nCols - 1; c++) {
int val = Integer.parseInt(row[c - 1]);
if (val > 0)
lst.add(val);
if (val == 1) {
startRow = r;
startCol = c;
}
grid[r][c] = val;
}
}
}
clues = lst.stream().sorted().mapToInt(i -> i).toArray();
if (solve(startRow, startCol, 1, 0))
printResult();
}
static boolean solve(int r, int c, int count, int nextClue) {
if (count > totalToFill)
return true;
if (grid[r][c] != 0 && grid[r][c] != count)
return false;
if (grid[r][c] == 0 && nextClue < clues.length)
if (clues[nextClue] == count)
return false;
int back = grid[r][c];
if (back == count)
nextClue++;
grid[r][c] = count;
for (int[] move : moves)
if (solve(r + move[1], c + move[0], count + 1, nextClue))
return true;
grid[r][c] = back;
return false;
}
static void printResult() {
for (int[] row : grid) {
for (int i : row) {
if (i == -1)
continue;
System.out.printf("%2d ", i);
}
System.out.println();
}
}
}