Last update: 27.07.2015
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Did you know that Heidi the Coding Cow is meant to defend the world from space invaders? Well, neither did she. No wonder she is completely flabbergasted as she is rushed into the Helvetic Conquest Cruiser and given the task to intercept the first wave of invaders. Therefore, she needs your help!

Given a 2D overview of the situation (v = invader, A = Helvetic Conquest Cruiser, _ = space) give Heidi the sequence of commands with least amount of steps that will make her take out the invaders, from the closest to earth to the furthest (that is, start with the row just above the 'A', then go up row by row). To make things easier, there is exactly one invader in a given row (except the bottommost).

The commands are Xl, Xr and s, where l/r means left/right and s means shoot. Replace X with the distance (columns) to move in the given direction.

A shot instantaneously takes out the bottommost surviving invader that is in the same column as the Helvetic Conquest Cruiser. You can assume that the invaders don't move. Concatenate your commands into a single string.

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For the following example scenario:


You should give the following command sequence:


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