Only store the most constrained move

1 files changed, 10 insertions, 13 deletions

diff --git a/src/main.zig b/src/main.zig
index 265425a..d5830b7 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -52,11 +52,7 @@ const SudokuSolver = struct {
     fn solve(self: *SudokuSolver) bool {
         if (self.isSolved()) return true;
 
-        // Variables to track the most constrained cell
-        var min_row: usize = 0;
-        var min_col: usize = 0;
-        var min_moves: ?std.StaticBitSet(9) = null;
-        var min_count: usize = 10; // More than maximum possible (9)
+        var most_constrained_moves: ?PossibleMoves = null;
 
         for (self.rows, 0..) |r, row| {
             for (@as([9]u8, r), 0..) |cell, col| {
@@ -72,24 +68,25 @@ const SudokuSolver = struct {
                             return self.solve();
                         },
                         0 => return false,
-                        else => |c| if (c < min_count) {
-                            min_row = row;
-                            min_col = col;
-                            min_moves = current_possible_moves;
-                            min_count = c;
+                        else => |c| if (most_constrained_moves == null or c < most_constrained_moves.?.moves.count()) {
+                            most_constrained_moves = .{
+                                .row = row,
+                                .col = col,
+                                .moves = current_possible_moves,
+                            };
                         },
                     }
                 }
             }
         }
 
-        if (min_moves) |pm| {
-            var moves_iter = pm.iterator(.{});
+        if (most_constrained_moves) |pm| {
+            var moves_iter = pm.moves.iterator(.{});
 
             while (moves_iter.next()) |current_move| {
                 const backup = self.*;
 
-                self.setCell(min_row, min_col, @intCast(current_move + 1));
+                self.setCell(pm.row, pm.col, @intCast(current_move + 1));
 
                 if (self.solve()) {
                     return true;