added winner() method

rdraught/examples/checkers.rs

@@ -15,7 +15,7 @@ fn main() {
     pieces.push(Piece::CrownedRedPawn).unwrap();
 
     board
-        .pieces(&pieces)
+        .pieces(pieces)
         .for_each(|pos| println!("({}, {}): {:?}", pos.row(), pos.col(), board[pos]));
     // println!("{:?}", board[Position::new(0, 0)]);
 

rdraught/src/draughts.rs

@@ -492,6 +492,17 @@ impl DraughtsGame {
         };
         (best_move, analyzed_moves)
     }
+
+    pub fn winner(&self) -> Option<Player> {
+        if self.available_moves().next().is_none() {
+            Some(match self.next_move {
+                Player::White => Player::Red,
+                Player::Red => Player::White,
+            })
+        } else {
+            None
+        }
+    }
 }
 #[derive(Debug, PartialEq, Eq)]
 struct MoveHeapEntry {