2019 Day 3 done!

2019/day03/problem

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+Advent of Code
+
+--- Day 3: Crossed Wires ---
+
+   The gravity assist was successful, and you're well on your way to the Venus refuelling station. During the rush back on Earth, the fuel management
+   system wasn't completely installed, so that's next on the priority list.
+
+   Opening the front panel reveals a jumble of wires. Specifically, two wires are connected to a central port and extend outward on a grid. You trace the
+   path each wire takes as it leaves the central port, one wire per line of text (your puzzle input).
+
+   The wires twist and turn, but the two wires occasionally cross paths. To fix the circuit, you need to find the intersection point closest to the central
+   port. Because the wires are on a grid, use the Manhattan distance for this measurement. While the wires do technically cross right at the central port
+   where they both start, this point does not count, nor does a wire count as crossing with itself.
+
+   For example, if the first wire's path is R8,U5,L5,D3, then starting from the central port (o), it goes right 8, up 5, left 5, and finally down 3:
+
+ ...........
+ ...........
+ ...........
+ ....+----+.
+ ....|....|.
+ ....|....|.
+ ....|....|.
+ .........|.
+ .o-------+.
+ ...........
+
+   Then, if the second wire's path is U7,R6,D4,L4, it goes up 7, right 6, down 4, and left 4:
+
+ ...........
+ .+-----+...
+ .|.....|...
+ .|..+--X-+.
+ .|..|..|.|.
+ .|.-X--+.|.
+ .|..|....|.
+ .|.......|.
+ .o-------+.
+ ...........
+
+   These wires cross at two locations (marked X), but the lower-left one is closer to the central port: its distance is 3 + 3 = 6.
+
+   Here are a few more examples:
+
+     • R75,D30,R83,U83,L12,D49,R71,U7,L72
+       U62,R66,U55,R34,D71,R55,D58,R83 = distance 159
+     • R98,U47,R26,D63,R33,U87,L62,D20,R33,U53,R51
+       U98,R91,D20,R16,D67,R40,U7,R15,U6,R7 = distance 135
+
+   What is the Manhattan distance from the central port to the closest intersection?
+
+--- Part Two ---
+
+   It turns out that this circuit is very timing-sensitive; you actually need to minimize the signal delay.
+
+   To do this, calculate the number of steps each wire takes to reach each intersection; choose the intersection where the sum of both wires' steps is
+   lowest. If a wire visits a position on the grid multiple times, use the steps value from the first time it visits that position when calculating the
+   total value of a specific intersection.
+
+   The number of steps a wire takes is the total number of grid squares the wire has entered to get to that location, including the intersection being
+   considered. Again consider the example from above:
+
+ ...........
+ .+-----+...
+ .|.....|...
+ .|..+--X-+.
+ .|..|..|.|.
+ .|.-X--+.|.
+ .|..|....|.
+ .|.......|.
+ .o-------+.
+ ...........
+
+   In the above example, the intersection closest to the central port is reached after 8+5+5+2 = 20 steps by the first wire and 7+6+4+3 = 20 steps by the
+   second wire for a total of 20+20 = 40 steps.
+
+   However, the top-right intersection is better: the first wire takes only 8+5+2 = 15 and the second wire takes only 7+6+2 = 15, a total of 15+15 = 30
+   steps.
+
+   Here are the best steps for the extra examples from above:
+
+     • R75,D30,R83,U83,L12,D49,R71,U7,L72
+       U62,R66,U55,R34,D71,R55,D58,R83 = 610 steps
+     • R98,U47,R26,D63,R33,U87,L62,D20,R33,U53,R51
+       U98,R91,D20,R16,D67,R40,U7,R15,U6,R7 = 410 steps
+
+   What is the fewest combined steps the wires must take to reach an intersection?
+
+   Both parts of this puzzle are complete! They provide two gold stars: **
+
+   At this point, you should return to your Advent calendar and try another puzzle.
+
+   If you still want to see it, you can get your puzzle input.
+
+References
+
+   Visible links
+   . https://adventofcode.com/
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+   . Advent of Code Supporter
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+   . https://adventofcode.com/2019/sponsors
+   . https://en.wikipedia.org/wiki/Taxicab_geometry
+   . https://adventofcode.com/2019
+   . https://adventofcode.com/2019/day/3/input