Cheapest Direction Repair
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Hard
Cheapest Direction Repair
A robot is placed in the top-left room of a rectangular control grid. Each room contains a command: 1 sends the robot right, 2 sends it left, 3 sends it down, and 4 sends it up. You may rewrite any room command, and each rewrite costs 1. Return the minimum total cost needed so the robot can follow commands from the top-left room to the bottom-right room.
Examples
Example 1
Input:
2 2 1 3 1 3
Output:
0
Explanation: The existing commands already allow a path from the start to the target.
Approach hint
Moving in the cell's current direction costs 0; choosing any other direction costs 1.
Common mistake
Skipping assumptions, edge cases, or trade-offs can make an otherwise good answer feel incomplete.
solution.cpp