new structure for 2018, added license information

2018/06/README.md

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+# 2018 Day 6: Chronal Coordinates
+Copyright (c) Eric Wastl 
+#### [Direct Link](https://adventofcode.com/2018/day/6)
+
+## Part 1
+
+The device on your wrist beeps several times, and once again you feel like you're falling.
+
+"Situation critical," the device announces. "Destination indeterminate. Chronal interference detected. Please specify new target coordinates."
+
+The device then produces a list of coordinates (your puzzle input). Are they places it thinks are safe or dangerous? It recommends you check manual page 729. The Elves did not give you a manual.
+
+**If they're dangerous**, maybe you can minimize the danger by finding the coordinate that gives the largest distance from the other points.
+
+Using only the [Manhattan distance](https://en.wikipedia.org/wiki/Taxicab_geometry), determine the **area** around each coordinate by counting the number of [integer](https://en.wikipedia.org/wiki/Integer) X,Y locations that are **closest** to that coordinate (and aren't **tied in distance** to any other coordinate).
+
+Your goal is to find the size of the **largest area** that isn't infinite. For example, consider the following list of coordinates:
+
+```
+1, 1
+1, 6
+8, 3
+3, 4
+5, 5
+8, 9
+```
+
+If we name these coordinates `A` through `F`, we can draw them on a grid, putting `0,0` at the top left:
+
+```
+..........
+.A........
+..........
+........C.
+...D......
+.....E....
+.B........
+..........
+..........
+........F.
+```
+
+This view is partial - the actual grid extends infinitely in all directions. Using the Manhattan distance, each location's closest coordinate can be determined, shown here in lowercase:
+
+```
+aaaaa.cccc
+aAaaa.cccc
+aaaddecccc
+aadddeccCc
+..dDdeeccc
+bb.deEeecc
+bBb.eeee..
+bbb.eeefff
+bbb.eeffff
+bbb.ffffFf
+```
+
+Locations shown as `.` are equally far from two or more coordinates, and so they don't count as being closest to any.
+
+In this example, the areas of coordinates A, B, C, and F are infinite - while not shown here, their areas extend forever outside the visible grid. However, the areas of coordinates D and E are finite: D is closest to 9 locations, and E is closest to 17 (both including the coordinate's location itself). Therefore, in this example, the size of the largest area is **17**.
+
+**What is the size of the largest area** that isn't infinite?
+
+## Part 2
+
+On the other hand, **if the coordinates are safe**, maybe the best you can do is try to find a **region** near as many coordinates as possible.
+
+For example, suppose you want the sum of the [Manhattan distance](https://en.wikipedia.org/wiki/Taxicab_geometry) to all of the coordinates to be **less than 32**. For each location, add up the distances to all of the given coordinates; if the total of those distances is less than 32, that location is within the desired region. Using the same coordinates as above, the resulting region looks like this:
+
+```
+..........
+.A........
+..........
+...###..C.
+..#D###...
+..###E#...
+.B.###....
+..........
+..........
+........F.
+```
+
+In particular, consider the highlighted location `4,3` located at the top middle of the region. Its calculation is as follows, where `abs()` is the [absolute value](https://en.wikipedia.org/wiki/Absolute_value) function:
+
+- Distance to coordinate A: `abs(4-1) + abs(3-1) =  5`
+- Distance to coordinate B: `abs(4-1) + abs(3-6) =  6`
+- Distance to coordinate C: `abs(4-8) + abs(3-3) =  4`
+- Distance to coordinate D: `abs(4-3) + abs(3-4) =  2`
+- Distance to coordinate E: `abs(4-5) + abs(3-5) =  3`
+- Distance to coordinate F: `abs(4-8) + abs(3-9) = 10`
+- Total distance: `5 + 6 + 4 + 2 + 3 + 10 = 30`
+
+Because the total distance to all coordinates (`30`) is less than 32, the location is **within** the region.
+
+This region, which also includes coordinates D and E, has a total size of **16**.
+
+Your actual region will need to be much larger than this example, though, instead including all locations with a total distance of less than **10000**.
+
+**What is the size of the region containing all locations which have a total distance to all given coordinates of less than 10000?**