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--- Day 12: Rain Risk ---
Your ferry made decent progress toward the island, but the storm came in faster than anyone
expected. The ferry needs to take [1m[37mevasive actions[0m!
Unfortunately, the ship's navigation computer seems to be malfunctioning; rather than giving a route
directly to safety, it produced extremely circuitous instructions. When the captain uses the PA
system to ask if anyone can help, you quickly volunteer.
The navigation instructions (your puzzle input) consists of a sequence of single-character
[1m[37mactions[0m paired with integer input [1m[37mvalues[0m. After staring at them for a few
minutes, you work out what they probably mean:
- Action [1m[37mN[0m means to move [1m[37mnorth[0m by the given value.
- Action [1m[37mS[0m means to move [1m[37msouth[0m by the given value.
- Action [1m[37mE[0m means to move [1m[37meast[0m by the given value.
- Action [1m[37mW[0m means to move [1m[37mwest[0m by the given value.
- Action [1m[37mL[0m means to turn [1m[37mleft[0m the given number of degrees.
- Action [1m[37mR[0m means to turn [1m[37mright[0m the given number of degrees.
- Action [1m[37mF[0m means to move [1m[37mforward[0m by the given value in the direction the
ship is currently facing.
The ship starts by facing [1m[37meast[0m. Only the L and R actions change the direction the ship
is facing. (That is, if the ship is facing east and the next instruction is N10, the ship would move
north 10 units, but would still move east if the following action were F.)
For example:
F10
N3
F7
R90
F11
These instructions would be handled as follows:
- F10 would move the ship 10 units east (because the ship starts by facing east) to [1m[37meast
10, north 0[0m.
- N3 would move the ship 3 units north to [1m[37meast 10, north 3[0m.
- F7 would move the ship another 7 units east (because the ship is still facing east) to
[1m[37meast 17, north 3[0m.
- R90 would cause the ship to turn right by 90 degrees and face [1m[37msouth[0m; it remains at
[1m[37meast 17, north 3[0m.
- F11 would move the ship 11 units south to [1m[37meast 17, south 8[0m.
At the end of these instructions, the ship's Manhattan distance (sum of the absolute values of its
east/west position and its north/south position) from its starting position is 17 + 8 =
[1m[37m25[0m.
Figure out where the navigation instructions lead. [1m[37mWhat is the Manhattan distance between
that location and the ship's starting position?[0m
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