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Solution: Number of Spaces Cleaning Robot Cleaned

Explore the step-by-step solution to the matrix cleaning robot challenge. Understand how the robot moves, tracks directions, and stops at repeated states. Learn to apply bitwise operations and matrix traversal techniques to count unique cleaned spaces, optimizing time and space complexity for an efficient solution.

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Statement

You are given a 0-indexed 2D binary matrix, room, representing a room of size m×nm \times n. In this matrix, 00 represents an empty space, while 11 represents a space occupied by an object. The top-left corner of the room is always empty in all test cases.

A cleaning robot starts at the top-left corner of the room, facing right. It moves straight until it either reaches the edge of the room or encounters an object. When this happens, it turns 90 degrees clockwise and continues moving. The robot cleans the starting space and every space it visits.

The robot continues moving indefinitely. If it visits a space again while facing the same direction, return the number of unique spaces it has cleaned.

Constraints:

  • m==m == room.length

  • n==n == ...