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|
--- Day 20: Jurassic Jigsaw ---
The high-speed train leaves the forest and quickly carries you south. You can even see a desert in
the distance! Since you have some spare time, you might as well see if there was anything
interesting in the image the Mythical Information Bureau satellite captured.
After decoding the satellite messages, you discover that the data actually contains many small
images created by the satellite's [1m[37mcamera array[0m. The camera array consists of many
cameras; rather than produce a single square image, they produce many smaller square image
[1m[37mtiles[0m that need to be [1m[37mreassembled back into a single image[0m.
Each camera in the camera array returns a single monochrome [1m[37mimage tile[0m with a random
unique [1m[37mID number[0m. The tiles (your puzzle input) arrived in a random order.
Worse yet, the camera array appears to be malfunctioning: each image tile has been [1m[37mrotated
and flipped to a random orientation[0m. Your first task is to reassemble the original image by
orienting the tiles so they fit together.
To show how the tiles should be reassembled, each tile's image data includes a border that should
line up exactly with its adjacent tiles. All tiles have this border, and the border lines up exactly
when the tiles are both oriented correctly. Tiles at the edge of the image also have this border,
but the outermost edges won't line up with any other tiles.
For example, suppose you have the following nine tiles:
Tile 2311:
..##.#..#.
##..#.....
#...##..#.
####.#...#
##.##.###.
##...#.###
.#.#.#..##
..#....#..
###...#.#.
..###..###
Tile 1951:
#.##...##.
#.####...#
.....#..##
#...######
.##.#....#
.###.#####
###.##.##.
.###....#.
..#.#..#.#
#...##.#..
Tile 1171:
####...##.
#..##.#..#
##.#..#.#.
.###.####.
..###.####
.##....##.
.#...####.
#.##.####.
####..#...
.....##...
Tile 1427:
###.##.#..
.#..#.##..
.#.##.#..#
#.#.#.##.#
....#...##
...##..##.
...#.#####
.#.####.#.
..#..###.#
..##.#..#.
Tile 1489:
##.#.#....
..##...#..
.##..##...
..#...#...
#####...#.
#..#.#.#.#
...#.#.#..
##.#...##.
..##.##.##
###.##.#..
Tile 2473:
#....####.
#..#.##...
#.##..#...
######.#.#
.#...#.#.#
.#########
.###.#..#.
########.#
##...##.#.
..###.#.#.
Tile 2971:
..#.#....#
#...###...
#.#.###...
##.##..#..
.#####..##
.#..####.#
#..#.#..#.
..####.###
..#.#.###.
...#.#.#.#
Tile 2729:
...#.#.#.#
####.#....
..#.#.....
....#..#.#
.##..##.#.
.#.####...
####.#.#..
##.####...
##..#.##..
#.##...##.
Tile 3079:
#.#.#####.
.#..######
..#.......
######....
####.#..#.
.#...#.##.
#.#####.##
..#.###...
..#.......
..#.###...
By rotating, flipping, and rearranging them, you can find a square arrangement that causes all
adjacent borders to line up:
#...##.#.. ..###..### #.#.#####.
..#.#..#.# ###...#.#. .#..######
.###....#. ..#....#.. ..#.......
###.##.##. .#.#.#..## ######....
.###.##### ##...#.### ####.#..#.
.##.#....# ##.##.###. .#...#.##.
#...###### ####.#...# #.#####.##
.....#..## #...##..#. ..#.###...
#.####...# ##..#..... ..#.......
#.##...##. ..##.#..#. ..#.###...
#.##...##. ..##.#..#. ..#.###...
##..#.##.. ..#..###.# ##.##....#
##.####... .#.####.#. ..#.###..#
####.#.#.. ...#.##### ###.#..###
.#.####... ...##..##. .######.##
.##..##.#. ....#...## #.#.#.#...
....#..#.# #.#.#.##.# #.###.###.
..#.#..... .#.##.#..# #.###.##..
####.#.... .#..#.##.. .######...
...#.#.#.# ###.##.#.. .##...####
...#.#.#.# ###.##.#.. .##...####
..#.#.###. ..##.##.## #..#.##..#
..####.### ##.#...##. .#.#..#.##
#..#.#..#. ...#.#.#.. .####.###.
.#..####.# #..#.#.#.# ####.###..
.#####..## #####...#. .##....##.
##.##..#.. ..#...#... .####...#.
#.#.###... .##..##... .####.##.#
#...###... ..##...#.. ...#..####
..#.#....# ##.#.#.... ...##.....
For reference, the IDs of the above tiles are:
[1m[37m1951[0m 2311 [1m[37m3079[0m
2729 1427 2473
[1m[37m2971[0m 1489 [1m[37m1171[0m
To check that you've assembled the image correctly, multiply the IDs of the four corner tiles
together. If you do this with the assembled tiles from the example above, you get 1951 * 3079 * 2971
* 1171 = [1m[37m20899048083289[0m.
Assemble the tiles into an image. [1m[37mWhat do you get if you multiply together the IDs of the
four corner tiles?[0m
|
