Question
A delivery robot moves on a grid of characters: 'S' start, 'T' target, '.' open, '#' wall, 'F' fuel station. Each step into an open/target/fuel cell consumes 1 unit of fuel; the robot starts full with `capacity` units and cannot move with 0 fuel remaining. Stepping onto an 'F' cell refills fuel back to `capacity` (after paying the 1 unit to enter it). Return the minimum number of steps to reach 'T', or -1 if impossible. The grid has exactly one 'S' and one 'T'.
min_steps_with_fuel(grid: list[list[str]], capacity: int) → int[[["S",".",".","T"]],5]out3State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.
Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.