tic tac toe

src/minmax.rs

@@ -1,73 +0,0 @@
-use crate::{
-    board::{Player, State},
-    Board, GamePlayer,
-};
-
-#[derive(PartialEq, Eq, PartialOrd, Ord)]
-struct Score(isize);
-
-#[derive(Clone)]
-pub struct PerfectPlayer {
-    best_move: usize,
-}
-
-impl PerfectPlayer {
-    pub fn new() -> Self {
-        Self {
-            best_move: usize::MAX,
-        }
-    }
-
-    fn minmax(&mut self, board: &mut Board, player: Player, depth: usize) -> Score {
-        match board.result() {
-            State::Winner(winner) => {
-                if winner == player {
-                    Score(1)
-                } else {
-                    Score(-1)
-                }
-            }
-            State::Draw => Score(0),
-            State::InProgress => {
-                let mut max_value = Score(isize::MIN);
-
-                debug_assert!(
-                    !board.iter().all(|x| x.is_some()),
-                    "the board is full but state is InProgress"
-                );
-
-                for (i, pos) in board.iter().enumerate() {
-                    if pos.is_some() {
-                        continue;
-                    }
-
-                    board.set(i, Some(player));
-                    let value = self.minmax(board, player.opponent(), depth + 1);
-                    board.set(i, None);
-
-                    if value > max_value {
-                        max_value = value;
-                        if depth == 0 {
-                            self.best_move = i;
-                        }
-                    }
-                }
-
-                max_value
-            }
-        }
-    }
-}
-
-impl GamePlayer for PerfectPlayer {
-    fn next_move(&mut self, board: &mut Board, this_player: Player) {
-        self.best_move = usize::MAX;
-        self.minmax(board, this_player, 0);
-
-        if self.best_move == usize::MAX {
-            panic!("could not make a move");
-        }
-
-        board.set(self.best_move, Some(this_player));
-    }
-}