387 lines
7.0 KiB
Plaintext
387 lines
7.0 KiB
Plaintext
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# Advent of Code
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--- Day 11: Dumbo Octopus ---
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You enter a large cavern full of rare bioluminescent dumbo octopuses! They seem to not like the Christmas lights on your submarine, so you turn
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them off for now.
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There are 100 octopuses arranged neatly in a 10 by 10 grid. Each octopus slowly gains energy over time and flashes brightly for a moment when its
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energy is full. Although your lights are off, maybe you could navigate through the cave without disturbing the octopuses if you could predict
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when the flashes of light will happen.
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Each octopus has an energy level - your submarine can remotely measure the energy level of each octopus (your puzzle input). For example:
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5483143223
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2745854711
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5264556173
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6141336146
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6357385478
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4167524645
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2176841721
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6882881134
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4846848554
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5283751526
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The energy level of each octopus is a value between 0 and 9. Here, the top-left octopus has an energy level of 5, the bottom-right one has an
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energy level of 6, and so on.
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You can model the energy levels and flashes of light in steps. During a single step, the following occurs:
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• First, the energy level of each octopus increases by 1.
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• Then, any octopus with an energy level greater than 9 flashes. This increases the energy level of all adjacent octopuses by 1, including
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octopuses that are diagonally adjacent. If this causes an octopus to have an energy level greater than 9, it also flashes. This process
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continues as long as new octopuses keep having their energy level increased beyond 9. (An octopus can only flash at most once per step.)
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• Finally, any octopus that flashed during this step has its energy level set to 0, as it used all of its energy to flash.
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Adjacent flashes can cause an octopus to flash on a step even if it begins that step with very little energy. Consider the middle octopus with 1
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energy in this situation:
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Before any steps:
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11111
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19991
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19191
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19991
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11111
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After step 1:
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34543
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40004
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50005
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40004
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34543
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After step 2:
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45654
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51115
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61116
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51115
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45654
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An octopus is highlighted when it flashed during the given step.
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Here is how the larger example above progresses:
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Before any steps:
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5483143223
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2745854711
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5264556173
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6141336146
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6357385478
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4167524645
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2176841721
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6882881134
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4846848554
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5283751526
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After step 1:
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6594254334
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3856965822
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6375667284
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7252447257
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7468496589
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5278635756
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3287952832
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7993992245
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5957959665
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6394862637
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After step 2:
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8807476555
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5089087054
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8597889608
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8485769600
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8700908800
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6600088989
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6800005943
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0000007456
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9000000876
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8700006848
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After step 3:
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0050900866
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8500800575
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9900000039
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9700000041
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9935080063
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7712300000
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7911250009
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2211130000
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0421125000
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0021119000
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After step 4:
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2263031977
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0923031697
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0032221150
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0041111163
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0076191174
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0053411122
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0042361120
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5532241122
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1532247211
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1132230211
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After step 5:
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4484144000
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2044144000
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2253333493
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1152333274
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1187303285
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1164633233
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1153472231
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6643352233
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2643358322
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2243341322
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After step 6:
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5595255111
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3155255222
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3364444605
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2263444496
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2298414396
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2275744344
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2264583342
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7754463344
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3754469433
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3354452433
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After step 7:
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6707366222
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4377366333
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4475555827
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3496655709
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3500625609
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3509955566
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3486694453
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8865585555
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4865580644
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4465574644
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After step 8:
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7818477333
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5488477444
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5697666949
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4608766830
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4734946730
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4740097688
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6900007564
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0000009666
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8000004755
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6800007755
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After step 9:
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9060000644
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7800000976
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6900000080
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5840000082
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5858000093
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6962400000
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8021250009
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2221130009
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9111128097
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7911119976
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After step 10:
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0481112976
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0031112009
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0041112504
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0081111406
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0099111306
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0093511233
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0442361130
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5532252350
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0532250600
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0032240000
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After step 10, there have been a total of 204 flashes. Fast forwarding, here is the same configuration every 10 steps:
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After step 20:
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3936556452
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5686556806
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4496555690
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4448655580
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4456865570
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5680086577
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7000009896
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0000000344
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6000000364
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4600009543
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After step 30:
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0643334118
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4253334611
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3374333458
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2225333337
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2229333338
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2276733333
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2754574565
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5544458511
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9444447111
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7944446119
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After step 40:
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6211111981
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0421111119
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0042111115
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0003111115
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0003111116
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0065611111
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0532351111
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3322234597
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2222222976
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2222222762
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After step 50:
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9655556447
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4865556805
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4486555690
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4458655580
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4574865570
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5700086566
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6000009887
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8000000533
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6800000633
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5680000538
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After step 60:
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2533334200
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2743334640
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2264333458
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2225333337
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2225333338
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2287833333
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3854573455
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1854458611
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1175447111
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1115446111
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After step 70:
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8211111164
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0421111166
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0042111114
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0004211115
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0000211116
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0065611111
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0532351111
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7322235117
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5722223475
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4572222754
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After step 80:
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1755555697
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5965555609
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4486555680
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4458655580
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4570865570
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5700086566
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7000008666
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0000000990
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0000000800
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0000000000
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After step 90:
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7433333522
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2643333522
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2264333458
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2226433337
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2222433338
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2287833333
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2854573333
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4854458333
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3387779333
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3333333333
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After step 100:
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0397666866
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0749766918
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0053976933
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0004297822
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0004229892
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0053222877
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0532222966
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9322228966
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7922286866
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6789998766
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After 100 steps, there have been a total of 1656 flashes.
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Given the starting energy levels of the dumbo octopuses in your cavern, simulate 100 steps. How many total flashes are there after 100 steps?
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Your puzzle answer was 1659.
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--- Part Two ---
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It seems like the individual flashes aren't bright enough to navigate. However, you might have a better option: the flashes seem to be
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synchronizing!
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In the example above, the first time all octopuses flash simultaneously is step 195:
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After step 193:
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5877777777
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8877777777
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7777777777
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7777777777
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7777777777
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7777777777
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7777777777
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7777777777
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7777777777
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7777777777
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After step 194:
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6988888888
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9988888888
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8888888888
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8888888888
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8888888888
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8888888888
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8888888888
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8888888888
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8888888888
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8888888888
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After step 195:
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0000000000
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0000000000
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0000000000
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0000000000
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0000000000
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0000000000
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0000000000
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0000000000
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0000000000
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0000000000
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If you can calculate the exact moments when the octopuses will all flash simultaneously, you should be able to navigate through the cavern. What
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is the first step during which all octopuses flash?
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Your puzzle answer was 227.
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Both parts of this puzzle are complete! They provide two gold stars: **
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At this point, you should return to your Advent calendar and try another puzzle.
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If you still want to see it, you can get your puzzle input.
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References
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Visible links
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. https://adventofcode.com/
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. https://adventofcode.com/2021/about
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. https://adventofcode.com/2021/events
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. https://adventofcode.com/2021/settings
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. https://adventofcode.com/2021/auth/logout
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. Advent of Code Supporter
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https://adventofcode.com/2021/support
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. https://adventofcode.com/2021
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. https://adventofcode.com/2021
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. https://adventofcode.com/2021/support
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. https://adventofcode.com/2021/sponsors
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. https://adventofcode.com/2021/leaderboard
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. https://adventofcode.com/2021/stats
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. https://adventofcode.com/2021/sponsors
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. https://www.youtube.com/watch?v=eih-VSaS2g0
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. https://adventofcode.com/2021
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. https://adventofcode.com/2021/day/11/input
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. javascript:void(0);
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