Initial data commit

Task/Find-Chess960-starting-position-identifier/Python/find-chess960-starting-position-identifier.py

@@ -0,0 +1,71 @@
+# optional, but task function depends on it as written
+def validate_position(candidate: str):
+    assert (
+        len(candidate) == 8
+    ), f"candidate position has invalide len = {len(candidate)}"
+
+    valid_pieces = {"R": 2, "N": 2, "B": 2, "Q": 1, "K": 1}
+    assert {
+        piece for piece in candidate
+    } == valid_pieces.keys(), f"candidate position contains invalid pieces"
+    for piece_type in valid_pieces.keys():
+        assert (
+            candidate.count(piece_type) == valid_pieces[piece_type]
+        ), f"piece type '{piece_type}' has invalid count"
+
+    bishops_pos = [index for index,
+                   value in enumerate(candidate) if value == "B"]
+    assert (
+        bishops_pos[0] % 2 != bishops_pos[1] % 2
+    ), f"candidate position has both bishops in the same color"
+
+    assert [piece for piece in candidate if piece in "RK"] == [
+        "R",
+        "K",
+        "R",
+    ], "candidate position has K outside of RR"
+
+
+def calc_position(start_pos: str):
+    try:
+        validate_position(start_pos)
+    except AssertionError:
+        raise AssertionError
+    # step 1
+    subset_step1 = [piece for piece in start_pos if piece not in "QB"]
+    nights_positions = [
+        index for index, value in enumerate(subset_step1) if value == "N"
+    ]
+    nights_table = {
+        (0, 1): 0,
+        (0, 2): 1,
+        (0, 3): 2,
+        (0, 4): 3,
+        (1, 2): 4,
+        (1, 3): 5,
+        (1, 4): 6,
+        (2, 3): 7,
+        (2, 4): 8,
+        (3, 4): 9,
+    }
+    N = nights_table.get(tuple(nights_positions))
+
+    # step 2
+    subset_step2 = [piece for piece in start_pos if piece != "B"]
+    Q = subset_step2.index("Q")
+
+    # step 3
+    dark_squares = [
+        piece for index, piece in enumerate(start_pos) if index in range(0, 9, 2)
+    ]
+    light_squares = [
+        piece for index, piece in enumerate(start_pos) if index in range(1, 9, 2)
+    ]
+    D = dark_squares.index("B")
+    L = light_squares.index("B")
+
+    return 4 * (4 * (6*N + Q) + D) + L
+
+if __name__ == '__main__':
+    for example in ["QNRBBNKR", "RNBQKBNR", "RQNBBKRN", "RNQBBKRN"]:
+        print(f'Position: {example}; Chess960 PID= {calc_position(example)}')