mirror of
https://github.com/coding-horror/basic-computer-games.git
synced 2025-12-22 07:10:42 -08:00
Removed spaces from top-level directory names.
Spaces tend to cause annoyances in a Unix-style shell environment. This change fixes that.
This commit is contained in:
Chris Reuter
398
23_Checkers/python/checkers.py
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398
23_Checkers/python/checkers.py
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@@ -0,0 +1,398 @@
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"""
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CHECKERS
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How about a nice game of checkers?
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Ported by Dave LeCompte
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"""
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import collections
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PAGE_WIDTH = 64
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HUMAN_PLAYER = 1
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COMPUTER_PLAYER = -1
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HUMAN_PIECE = 1
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HUMAN_KING = 2
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COMPUTER_PIECE = -1
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COMPUTER_KING = -2
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EMPTY_SPACE = 0
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TOP_ROW = 7
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BOTTOM_ROW = 0
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MoveRecord = collections.namedtuple(
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"MoveRecord", ["quality", "start_x", "start_y", "dest_x", "dest_y"]
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)
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def print_centered(msg):
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spaces = " " * ((PAGE_WIDTH - len(msg)) // 2)
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print(spaces + msg)
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def print_header(title):
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print_centered(title)
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print_centered("CREATIVE COMPUTING MORRISTOWN, NEW JERSEY")
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print()
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print()
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print()
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def get_coordinates(prompt):
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err_msg = "ENTER COORDINATES in X,Y FORMAT"
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while True:
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print(prompt)
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response = input()
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if "," not in response:
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print(err_msg)
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continue
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try:
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x, y = [int(c) for c in response.split(",")]
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except ValueError as ve:
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print(err_msg)
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continue
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return x, y
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def is_legal_board_coordinate(x, y):
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return (0 <= x <= 7) and (0 <= y <= 7)
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class Board:
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def __init__(self):
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self.spaces = [[0 for y in range(8)] for x in range(8)]
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for x in range(8):
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if (x % 2) == 0:
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self.spaces[x][6] = COMPUTER_PIECE
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self.spaces[x][2] = HUMAN_PIECE
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self.spaces[x][0] = HUMAN_PIECE
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else:
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self.spaces[x][7] = COMPUTER_PIECE
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self.spaces[x][5] = COMPUTER_PIECE
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self.spaces[x][1] = HUMAN_PIECE
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def __str__(self):
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pieces = {
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EMPTY_SPACE: ".",
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HUMAN_PIECE: "O",
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HUMAN_KING: "O*",
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COMPUTER_PIECE: "X",
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COMPUTER_KING: "X*",
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}
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s = "\n\n\n"
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for y in range(7, -1, -1):
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for x in range(0, 8):
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piece_str = pieces[self.spaces[x][y]]
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piece_str += " " * (5 - len(piece_str))
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s += piece_str
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s += "\n"
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s += "\n\n"
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return s
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def get_spaces(self):
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for x in range(0, 8):
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for y in range(0, 8):
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yield x, y
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def get_spaces_with_computer_pieces(self):
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for x, y in self.get_spaces():
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contents = self.spaces[x][y]
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if contents < 0:
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yield x, y
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def get_spaces_with_human_pieces(self):
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for x, y in self.get_spaces():
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contents = self.spaces[x][y]
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if contents > 0:
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yield x, y
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def get_legal_deltas_for_space(self, x, y):
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contents = self.spaces[x][y]
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if contents == COMPUTER_PIECE:
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for delta_x in (-1, 1):
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yield (delta_x, -1)
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else:
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for delta_x in (-1, 1):
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for delta_y in (-1, 1):
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yield (delta_x, delta_y)
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def pick_computer_move(self):
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move_record = None
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for start_x, start_y in self.get_spaces_with_computer_pieces():
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for delta_x, delta_y in self.get_legal_deltas_for_space(start_x, start_y):
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new_move_record = self.check_move(start_x, start_y, delta_x, delta_y)
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if new_move_record is None:
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continue
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if (move_record is None) or (
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new_move_record.quality > move_record.quality
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):
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move_record = new_move_record
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return move_record
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def check_move(self, start_x, start_y, delta_x, delta_y):
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new_x = start_x + delta_x
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new_y = start_y + delta_y
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if not is_legal_board_coordinate(new_x, new_y):
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return None
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contents = self.spaces[new_x][new_y]
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if contents == EMPTY_SPACE:
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return self.evaluate_move(start_x, start_y, new_x, new_y)
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if contents < 0:
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return None
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# check jump landing space, which is an additional dx, dy from new_x, newy
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landing_x = new_x + delta_x
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landing_y = new_y + delta_y
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if not is_legal_board_coordinate(landing_x, landing_y):
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return None
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if self.spaces[landing_x][landing_y] == EMPTY_SPACE:
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return self.evaluate_move(start_x, start_y, landing_x, landing_y)
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def evaluate_move(self, start_x, start_y, dest_x, dest_y):
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quality = 0
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if dest_y == 0 and self.spaces[start_x][start_y] == COMPUTER_PIECE:
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# promoting is good
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quality += 2
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if abs(dest_y - start_y) == 2:
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# jumps are good
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quality += 5
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if start_y == 7:
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# prefer to defend back row
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quality -= 2
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if dest_x in (0, 7):
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# moving to edge column
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quality += 1
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for delta_x in (-1, 1):
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if not is_legal_board_coordinate(dest_x + delta_x, dest_y - 1):
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continue
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if self.spaces[dest_x + delta_x][dest_y - 1] < 0:
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# moving into "shadow" of another computer piece
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quality += 1
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if not is_legal_board_coordinate(dest_x - delta_x, dest_y + 1):
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continue
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if (
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(self.spaces[dest_x + delta_x][dest_y - 1] > 0)
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and (self.spaces[dest_x - delta_x][dest_y + 1] == EMPTY_SPACE)
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or ((dest_x - delta_x == start_x) and (dest_y + 1 == start_y))
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):
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# we are moving up to a human checker that could jump us
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quality -= 2
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return MoveRecord(quality, start_x, start_y, dest_x, dest_y)
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def remove_r_pieces(self, move_record):
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self.remove_pieces(
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move_record.start_x,
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move_record.start_y,
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move_record.dest_x,
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move_record.dest_y,
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)
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def remove_pieces(self, start_x, start_y, dest_x, dest_y):
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self.spaces[dest_x][dest_y] = self.spaces[start_x][start_y]
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self.spaces[start_x][start_y] = EMPTY_SPACE
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if abs(dest_x - start_x) == 2:
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mid_x = (start_x + dest_x) // 2
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mid_y = (start_y + dest_y) // 2
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self.spaces[mid_x][mid_y] = EMPTY_SPACE
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def play_computer_move(self, move_record):
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print(
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f"FROM {move_record.start_x} {move_record.start_y} TO {move_record.dest_x} {move_record.dest_y}"
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)
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while True:
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if move_record.dest_y == BOTTOM_ROW:
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# KING ME
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self.remove_r_pieces(move_record)
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self.spaces[move_record.dest_x][move_record.dest_y] = COMPUTER_KING
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return
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else:
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self.spaces[move_record.dest_x][move_record.dest_y] = self.spaces[
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move_record.start_x
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][move_record.start_y]
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self.remove_r_pieces(move_record)
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if abs(move_record.dest_x - move_record.start_x) != 2:
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return
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landing_x = move_record.dest_x
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landing_y = move_record.dest_y
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best_move = None
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if self.spaces[landing_x][landing_y] == COMPUTER_PIECE:
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for delta_x in (-2, 2):
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test_record = self.try_extend(landing_x, landing_y, delta_x, -2)
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if not (move_record is None):
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if (best_move is None) or (
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move_record.quality > best_move.quality
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):
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best_move = test_record
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else:
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assert self.spaces[landing_x][landing_y] == COMPUTER_KING
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for delta_x in (-2, 2):
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for delta_y in (-2, 2):
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test_record = self.try_extend(
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landing_x, landing_y, delta_x, delta_y
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)
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if not (move_record is None):
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if (best_move is None) or (
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move_record.quality > best_move.quality
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):
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best_move = test_record
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if best_move is None:
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return
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else:
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print(f"TO {best_move.dest_x} {best_move.dest_y}")
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move_record = best_move
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def try_extend(self, start_x, start_y, delta_x, delta_y):
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new_x = start_x + delta_x
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new_y = start_y + delta_y
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if not is_legal_board_coordinate(new_x, new_y):
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return None
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jumped_x = start_x + delta_x // 2
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jumped_y = start_y + delta_y // 2
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if (self.spaces[new_x][new_y] == EMPTY_SPACE) and (
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self.spaces[jumped_x][jumped_y] > 0
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):
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return self.evaluate_move(start_x, start_y, new_x, new_y)
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def get_human_move(self):
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is_king = False
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while True:
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start_x, start_y = get_coordinates("FROM?")
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if self.spaces[start_x][start_y] > 0:
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break
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is_king = self.spaces[start_x][start_y] == HUMAN_KING
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while True:
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dest_x, dest_y = get_coordinates("TO?")
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if (not is_king) and (dest_y < start_y):
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# CHEATER! Trying to move non-king backwards
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continue
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if (
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(self.spaces[dest_x][dest_y] == 0)
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and (abs(dest_x - start_x) <= 2)
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and (abs(dest_x - start_x) == abs(dest_y - start_y))
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):
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break
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return start_x, start_y, dest_x, dest_y
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def get_human_extension(self, start_x, start_y):
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is_king = self.spaces[start_x][start_y] == HUMAN_KING
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while True:
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dest_x, dest_y = get_coordinates("+TO?")
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if dest_x < 0:
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return False, None
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if (not is_king) and (dest_y < start_y):
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# CHEATER! Trying to move non-king backwards
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continue
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if (
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(self.spaces[dest_x][dest_y] == EMPTY_SPACE)
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and (abs(dest_x - start_x) == 2)
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and (abs(dest_y - start_y) == 2)
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):
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return True, (start_x, start_y, dest_x, dest_y)
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def play_human_move(self, start_x, start_y, dest_x, dest_y):
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self.remove_pieces(start_x, start_y, dest_x, dest_y)
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if dest_y == TOP_ROW:
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# KING ME
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self.spaces[dest_x][dest_y] = HUMAN_KING
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def check_pieces(self):
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if len(list(self.get_spaces_with_computer_pieces())) == 0:
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print_human_won()
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return False
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if len(list(self.get_spaces_with_computer_pieces())) == 0:
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print_computer_won()
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return False
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return True
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def print_instructions():
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print("THIS IS THE GAME OF CHECKERS. THE COMPUTER IS X,")
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print("AND YOU ARE O. THE COMPUTER WILL MOVE FIRST.")
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print("SQUARES ARE REFERRED TO BY A COORDINATE SYSTEM.")
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print("(0,0) IS THE LOWER LEFT CORNER")
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print("(0,7) IS THE UPPER LEFT CORNER")
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print("(7,0) IS THE LOWER RIGHT CORNER")
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print("(7,7) IS THE UPPER RIGHT CORNER")
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print("THE COMPUTER WILL TYPE '+TO' WHEN YOU HAVE ANOTHER")
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print("JUMP. TYPE TWO NEGATIVE NUMBERS IF YOU CANNOT JUMP.")
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print()
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print()
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print()
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def print_human_won():
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print()
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print("YOU WIN.")
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def print_computer_won():
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print()
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print("I WIN.")
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def play_game():
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board = Board()
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while True:
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move_record = board.pick_computer_move()
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if move_record is None:
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print_human_won()
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return
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board.play_computer_move(move_record)
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print(board)
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if not board.check_pieces():
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return
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start_x, start_y, dest_x, dest_y = board.get_human_move()
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board.play_human_move(start_x, start_y, dest_x, dest_y)
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if abs(dest_x - start_x) == 2:
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while True:
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extend, move = board.get_human_extension(dest_x, dest_y)
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if not extend:
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break
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start_x, start_y, dest_x, dest_y = move
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board.play_human_move(start_x, start_y, dest_x, dest_y)
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def main():
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print_header("CHECKERS")
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print_instructions()
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play_game()
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if __name__ == "__main__":
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main()
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Block a user