Data update

Task/Solve-a-Numbrix-puzzle/Dart/solve-a-numbrix-puzzle.dart

@@ -0,0 +1,92 @@
+/// Based on https://rosettacode.org/wiki/Solve_a_Numbrix_puzzle#Kotlin
+import 'package:more/more.dart';
+import 'package:sprintf/sprintf.dart';
+
+const examples = [
+  [
+    "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"
+  ],
+  [
+    "00,00,00,00,00,00,00,00,00",
+    "00,11,12,15,18,21,62,61,00",
+    "00,06,00,00,00,00,00,60,00",
+    "00,33,00,00,00,00,00,57,00",
+    "00,32,00,00,00,00,00,56,00",
+    "00,37,00,01,00,00,00,73,00",
+    "00,38,00,00,00,00,00,72,00",
+    "00,43,44,47,48,51,76,77,00",
+    "00,00,00,00,00,00,00,00,00"
+  ]
+];
+
+const moves = [
+  [1, 0],
+  [0, 1],
+  [-1, 0],
+  [0, -1]
+];
+
+late List<String> board;
+late List<List<int>> grid;
+late List<int> clues;
+var totalToFill = 0;
+
+bool solve(int r, int c, int count, int nextClue) {
+  if (count > totalToFill) return true;
+  var back = grid[r][c];
+  if (back != 0 && back != count) return false;
+  if (back == 0 && nextClue < clues.length && clues[nextClue] == count) {
+    return false;
+  }
+
+  var nextClue2 = nextClue;
+  if (back == count) nextClue2++;
+  grid[r][c] = count;
+  var res = moves.any((m) => solve(r + m[1], c + m[0], count + 1, nextClue2));
+  if (!res) grid[r][c] = back;
+  return res;
+}
+
+void printResult(int n) {
+  print("Solution for example $n:");
+  for (var row in grid) {
+    print([
+      for (var e in row)
+        if (e != -1) sprintf("%2d ", [e])
+    ].join());
+  }
+}
+
+main() {
+  for (var each in examples.indexed()) {
+    board = each.value;
+    var nRows = board.length + 2, nCols = board[0].split(",").length + 2;
+    var startRow = 0, startCol = 0;
+    grid = List.generate(nRows, (i) => List.filled(nCols, -1));
+    totalToFill = (nRows - 2) * (nCols - 2);
+    var lst = <int>[];
+    for (var r in 1.to(nRows - 1)) {
+      var row = board[r - 1].split(",");
+      for (var c in 1.to(nCols - 1)) {
+        var value = int.parse(row[c - 1]);
+        if (value > 0) lst.add(value);
+        if (value == 1) {
+          startRow = r;
+          startCol = c;
+        }
+        grid[r][c] = value;
+      }
+    }
+
+    clues = (lst..sort()).toList();
+    if (solve(startRow, startCol, 1, 0)) printResult(each.index + 1);
+  }
+}