Trying jump game again

leetcode/stuff.py

@@ -286,3 +286,71 @@ def binary_tree_from_preorder_inorder(
     split_pos = inorder.index(preorder[0])
 
     return subtree(inorder[:split_pos], inorder[split_pos + 1 :])
+
+
+class JumpSpace(typing.NamedTuple):
+    pos: int
+    val: int
+    moves: list["JumpSpace"]
+
+    @classmethod
+    def from_board(
+        cls, pos: int = 0, board: typing.Iterable[int] = ()
+    ) -> typing.Optional["JumpSpace"]:
+        board = list(board)
+
+        if len(board) == 0:
+            return None
+
+        space = cls(pos, board[pos], [])
+        space.collect(board)
+        return space
+
+    def collect(self, board: list[int]) -> None:
+        del self.moves[:]
+
+        if self.pos > len(board) or len(board) == 0:
+            return
+
+        for n in range(self.pos + 1, self.pos + self.val + 1):
+            if n >= len(board):
+                break
+
+            self.moves.append(typing.cast(JumpSpace, JumpSpace.from_board(n, board)))
+
+    def jump_paths(self) -> list[list[int]]:
+        ret: list[list[int]] = [[self.pos]]
+
+        for next_space in self.moves:
+            for path in next_space.jump_paths():
+                ret.append([self.pos] + path)
+
+        return ret
+
+
+def count_min_jumps_from_board(board: list[int]) -> int:
+    if len(board) == 1:
+        return 0
+
+    complete_paths = collect_complete_jump_paths_from_board(board)
+
+    if len(complete_paths) == 0:
+        return -1
+
+    return min([len(p) - 1 for p in complete_paths])
+
+
+def collect_complete_jump_paths_from_board(board: list[int]) -> list[list[int]]:
+    return [
+        p
+        for p in collect_jump_paths_from_board(board)
+        if len(p) > 0 and p[-1] >= len(board) - 1
+    ]
+
+
+def collect_jump_paths_from_board(board: list[int]) -> list[list[int]]:
+    space = JumpSpace.from_board(0, board)
+    if space is None:
+        return []
+
+    return space.jump_paths()

leetcode/test_stuff.py

@@ -249,3 +249,48 @@ def test_binary_tree_from_preorder_inorder(
     preorder: list[int], inorder: list[int], expected: stdlib.BinaryTreeNode
 ):
     assert stuff.binary_tree_from_preorder_inorder(preorder, inorder) == expected
+
+
+@pytest.mark.parametrize(
+    ("board", "expected"),
+    [
+        (
+            [2, 3, 1, 1, 4],
+            [
+                [0, 1, 2, 3, 4],
+                [0, 1, 3, 4],
+                [0, 1, 4],
+                [0, 2, 3, 4],
+            ],
+        ),
+    ],
+)
+def test_collect_complete_jump_paths_from_board(
+    board: list[int], expected: list[list[int]]
+):
+    assert list(sorted(stuff.collect_complete_jump_paths_from_board(board))) == expected
+
+
+@pytest.mark.parametrize(
+    ("board", "expected"),
+    [
+        (
+            [2, 3, 1, 1, 4],
+            2,
+        ),
+        (
+            [2, 3, 0, 1, 4],
+            2,
+        ),
+        (
+            [1],
+            0,
+        ),
+        (
+            [1, 2],
+            1,
+        ),
+    ],
+)
+def test_count_min_jumps_from_board(board: list[int], expected: int):
+    assert stuff.count_min_jumps_from_board(board) == expected