Fixed successors() function

Author: davecom

Chapter2/maze.py

@@ -68,11 +68,11 @@ def successors(self, ml: MazeLocation) -> List[MazeLocation]:
         locations: List[MazeLocation] = []
         if ml.row + 1 < self._rows and self._grid[ml.row + 1][ml.column] != Cell.BLOCKED:
             locations.append(MazeLocation(ml.row + 1, ml.column))
-        if ml.row - 1 > 0 and self._grid[ml.row - 1][ml.column] != Cell.BLOCKED:
+        if ml.row - 1 >= 0 and self._grid[ml.row - 1][ml.column] != Cell.BLOCKED:
             locations.append(MazeLocation(ml.row - 1, ml.column))
         if ml.column + 1 < self._columns and self._grid[ml.row][ml.column + 1] != Cell.BLOCKED:
             locations.append(MazeLocation(ml.row, ml.column + 1))
-        if ml.column - 1 > 0 and self._grid[ml.row][ml.column - 1] != Cell.BLOCKED:
+        if ml.column - 1 >= 0 and self._grid[ml.row][ml.column - 1] != Cell.BLOCKED:
             locations.append(MazeLocation(ml.row, ml.column - 1))
         return locations