Day 14

Author: tuukkasarvi

data/input_14.txt

@@ -0,0 +1,544 @@
+mask = 1100X10X01001X111001X00010X00100X011
+mem[24821] = 349
+mem[34917] = 13006
+mem[53529] = 733
+mem[50289] = 245744
+mem[23082] = 6267
+mask = 011X1X00X100100XXXX11100X0000100X010
+mem[21316] = 14188354
+mem[53283] = 7137
+mem[57344] = 62358
+mem[63867] = 9443
+mask = XXX00X0X0X000101000010001001X011X100
+mem[24644] = 116
+mem[48236] = 73606120
+mem[10510] = 38322
+mask = X1X110000X0X100X1101X00111010X011X10
+mem[34997] = 31342
+mem[26072] = 2268501
+mem[5252] = 632
+mem[7236] = 22768
+mem[49071] = 551093395
+mask = 01XX100001001X00XX1XX101100X00101001
+mem[54837] = 244218
+mem[21783] = 11585
+mem[21099] = 76905
+mem[2378] = 53200
+mem[26270] = 417292
+mem[45806] = 620
+mask = X11X0111X100X10100X0X1X011X10100111X
+mem[58750] = 183290
+mem[43104] = 86138
+mem[19509] = 11175103
+mem[49328] = 267886858
+mask = 000X110X01X0110100101X0X00XX00010001
+mem[59931] = 59583
+mem[32104] = 883
+mem[15538] = 243291
+mask = 001X1101010X11010XXX01010111101X00X1
+mem[8242] = 108187354
+mem[65087] = 38969853
+mem[48863] = 63153
+mem[25959] = 230061422
+mem[43740] = 368377
+mem[58841] = 4055593
+mem[59380] = 59386
+mask = 110110010100XX11XX010100100110001100
+mem[7020] = 447178
+mem[36813] = 2655
+mem[31309] = 1748
+mem[24822] = 5683403
+mem[60917] = 6812
+mask = 0XX1010X01X011X1X010X001110110100010
+mem[44478] = 1586539
+mem[39782] = 949
+mem[54286] = 96566
+mem[14466] = 99
+mem[20192] = 18086
+mem[3717] = 79648
+mem[58752] = 40328
+mask = 100X1X001X00111111X1100100X11XX0X101
+mem[18878] = 2450507
+mem[5564] = 1664611
+mem[9704] = 116868
+mem[21119] = 102749
+mem[25549] = 2173
+mem[63519] = 7948355
+mem[9402] = 29593133
+mask = X1101100110X10001111101X0X00X1000010
+mem[24578] = 16594035
+mem[12855] = 62817
+mem[19754] = 204831
+mem[39912] = 587039668
+mem[20004] = 1492295
+mem[17243] = 5531
+mem[1316] = 28121178
+mask = 001111XX01001X01001X111110X1101010X1
+mem[29079] = 3819301
+mem[43580] = 3021873
+mem[12717] = 91478
+mask = 111XX10X010X1011XX0100000000X0001X0X
+mem[21612] = 1342337
+mem[13794] = 6460
+mem[63974] = 79096
+mem[61231] = 79
+mem[52748] = 548989
+mask = 110X1X01010XXXX1X0010000101X011001X0
+mem[7150] = 129613326
+mem[2629] = 19221
+mem[34913] = 5720809
+mask = 0XX0X0X00100X1X00111011X111X10X11101
+mem[14506] = 808939
+mem[22097] = 3682116
+mem[45143] = 70886840
+mem[11000] = 823928
+mem[45922] = 709192
+mem[38124] = 21830062
+mask = 00XXX10X01001101X010XX10X1X100100010
+mem[54703] = 154976
+mem[12855] = 187248782
+mem[65457] = 28101
+mem[15696] = 2295684
+mem[30880] = 1247718
+mem[45160] = 515441
+mask = 1X110101010011X1100110X0001X01001100
+mem[57318] = 100074
+mem[47449] = 4621
+mem[59319] = 50563
+mem[41125] = 37890243
+mask = X11X0101010011X11001X010110100000010
+mem[50289] = 5524
+mem[42244] = 3206413
+mem[56334] = 869121
+mem[38672] = 1475
+mem[15747] = 203
+mem[24920] = 87767798
+mask = X111110X000010X1X00100011100X0011X11
+mem[21588] = 451
+mem[23953] = 46630
+mem[14775] = 49711378
+mem[50858] = 2467
+mask = 1101100001001X0110011001XXX11111X001
+mem[55659] = 1545765
+mem[6437] = 31978856
+mem[39782] = 14103777
+mem[36553] = 11829098
+mem[381] = 1092062
+mem[8934] = 730472
+mem[2555] = 1825500
+mask = 0XX0100X010010001X111X00100X01001X11
+mem[2219] = 43334
+mem[22560] = 1622449
+mem[43084] = 947441529
+mask = 110X1000010X1X1X100101010110000XX0X0
+mem[36928] = 489523
+mem[28368] = 13289
+mask = X111X10101001101X0XX1X0011X0000001XX
+mem[18457] = 3703
+mem[3623] = 32246635
+mem[24559] = 80719
+mem[58118] = 8905129
+mem[16253] = 45786863
+mem[40870] = 495305
+mem[9309] = 259478546
+mask = 01111100X1001XX10010X1100X1010010000
+mem[5294] = 197088
+mem[44504] = 10557956
+mem[59142] = 116862
+mask = 1X01X10100XXX0101XX1101X1000001011X1
+mem[16259] = 434323408
+mem[62326] = 739075
+mem[46819] = 13021
+mem[60917] = 2384
+mask = X1X01X0001001000001011010000X1101100
+mem[21341] = 70959125
+mem[62908] = 762
+mem[34493] = 484
+mem[17428] = 31
+mask = 01011011010110X10111110X00X1110010XX
+mem[18984] = 3776829
+mem[57419] = 6347092
+mask = 01X11101010011010010X0XX11X101X01100
+mem[3581] = 47227
+mem[15034] = 148249156
+mem[39328] = 32020553
+mem[45580] = 921
+mask = 1X11110X0000X0111001XX001X01100X1010
+mem[65437] = 31942299
+mem[41279] = 52981019
+mem[22939] = 30
+mask = 11011X0X01001XX11X010X01001111XX1X00
+mem[49334] = 2124
+mem[3052] = 75699
+mem[56099] = 206
+mask = X10X110001XX1011100X1001X0000XX01110
+mem[16214] = 194247445
+mem[5064] = 6545
+mem[24889] = 334318
+mem[60668] = 613191688
+mem[13452] = 2759371
+mask = XXX001X1010001010X0000X001X1X11011X0
+mem[41278] = 202539349
+mem[17818] = 6496568
+mem[51738] = 793135
+mask = 01110X1X0X00X10000X000X1011110001X00
+mem[54203] = 102262453
+mem[47434] = 11948539
+mem[4065] = 1955823
+mem[5838] = 116726352
+mem[22858] = 770
+mask = 1X0111010X10X01X100110001111X0X00X11
+mem[2486] = 828784
+mem[45704] = 52334
+mem[25505] = 7455952
+mem[35622] = 2191372
+mem[43475] = 1724531
+mem[51269] = 231866
+mask = 10011000XX001X1111XXXX0X00111000010X
+mem[1849] = 42419
+mem[4574] = 1532276
+mem[24053] = 414769
+mask = 1111X1X1XX0X10X110XX10001101101X1111
+mem[50131] = 380577
+mem[14034] = 324
+mem[43433] = 468143
+mem[57359] = 918
+mem[32101] = 671267
+mem[10229] = 779186
+mask = 110X1100010X11X110XX1101X01101011000
+mem[50062] = 1717353
+mem[44599] = 213984
+mem[2474] = 270288
+mem[25959] = 947
+mem[14725] = 59
+mem[43580] = 1510
+mask = 011XX10101001101X00111001101X0001100
+mem[56933] = 226
+mem[13318] = 4614
+mem[30661] = 15820
+mask = X1011100XX0X10111000X001110X00010X10
+mem[43263] = 15614563
+mem[58584] = 4208089
+mem[44934] = 1045
+mem[8892] = 7322
+mask = 1X011000X10010X111010001XX111001XX1X
+mem[49868] = 246
+mem[5838] = 22365009
+mem[41002] = 23308
+mem[20933] = 135967
+mem[28178] = 191447
+mem[12921] = 12366
+mask = 111X0X0X0100110100XX00000X0001000000
+mem[37981] = 3749401
+mem[26391] = 5633
+mem[32104] = 36834
+mem[44124] = 3460632
+mem[5838] = 491004585
+mask = 01000X1101X0010X0100X11011011111X0X0
+mem[23993] = 9267350
+mem[51536] = 1866241
+mem[40301] = 264185
+mem[65174] = 1500904
+mem[30449] = 2040
+mem[11574] = 31366391
+mask = X1X11101X1X010111X01100X0X100X00X101
+mem[51781] = 12168
+mem[39202] = 21507
+mask = 11011X00010X1X1X10011000XX1X01X00X10
+mem[14042] = 2091313
+mem[54126] = 926
+mem[54056] = 380624
+mem[4492] = 58611931
+mem[14287] = 2682945
+mask = 011000000X0X1X010X1101X0100000111000
+mem[37035] = 8382057
+mem[5086] = 105635
+mem[59782] = 287247
+mem[59842] = 261015
+mem[55905] = 427749005
+mem[38951] = 116871701
+mask = 011XXXX001001X0X001011X10100X0010100
+mem[37224] = 240173934
+mem[7233] = 4620173
+mem[11642] = 53937442
+mem[25130] = 31578
+mem[27305] = 19855
+mask = 01110111010011010X101X010X01111X10X0
+mem[9117] = 80452
+mem[45949] = 66133382
+mem[58118] = 431847
+mem[45227] = 31859837
+mem[12227] = 12785
+mem[10370] = 3992241
+mask = 011X01010X00X101X000101XX100X100X0X0
+mem[3584] = 98035933
+mem[48508] = 24604
+mask = 01101110010010X1001011X1X10000XX1X00
+mem[32223] = 13600
+mem[17788] = 30410813
+mask = 11X0110X0X00100000X011110101X1010000
+mem[54352] = 3305565
+mem[33020] = 56159
+mem[58750] = 3553365
+mask = 01110X0X010011010010100000000001X10X
+mem[45320] = 86117954
+mem[56412] = 32488
+mem[44120] = 27915
+mask = 1111110X0100X0010001X0101X0110111111
+mem[1600] = 3494
+mem[15191] = 8051858
+mem[4831] = 514
+mem[52749] = 3554802
+mem[14870] = 5452
+mask = X0X110X011001011110111000X11XX011010
+mem[32924] = 343831204
+mem[37938] = 206
+mem[29100] = 4279
+mask = 111X1101X11X101110X1110010100000000X
+mem[51565] = 21744022
+mem[17959] = 984
+mem[51269] = 546739474
+mask = X11X11000100110100100100010X110XX100
+mem[60489] = 1801861
+mem[10306] = 661
+mem[51002] = 1120331
+mem[4803] = 21542674
+mem[26350] = 878
+mem[42540] = 79468437
+mem[56396] = 6518705
+mask = 01XXX0XX010011X1X11111000X0011101X00
+mem[22955] = 1087
+mem[24644] = 31210240
+mem[11638] = 1408
+mem[22097] = 31493533
+mem[61231] = 2476899
+mask = X1011X011100101X11011100X010X0001101
+mem[56933] = 112988
+mem[60092] = 16076531
+mem[55659] = 668286721
+mem[56710] = 8215281
+mem[49668] = 5991824
+mem[49216] = 2918850
+mask = X001010101001111X010100X111X00100111
+mem[37025] = 17025
+mem[42119] = 410077231
+mask = 111X1101010X10011010X0X1011010001X11
+mem[31309] = 15349
+mem[47328] = 245527268
+mem[29215] = 1790
+mem[54165] = 6329067
+mem[11618] = 1311552
+mem[11994] = 15416
+mem[43900] = 4424
+mask = 00110X00X1011X000010X01100010101100X
+mem[31645] = 471
+mem[41596] = 13507488
+mem[11528] = 25929919
+mem[5643] = 56515
+mem[52143] = 74146
+mask = 0X11X1XX0100110X0010101011X1X1X01X00
+mem[4526] = 129045325
+mem[16253] = 15510
+mem[58841] = 114430082
+mem[63068] = 1155009
+mem[24644] = 95502013
+mask = 0110111001XX11000X1011001100XX0000X1
+mem[5333] = 7007
+mem[10355] = 3824
+mem[55659] = 33270617
+mem[61541] = 64962
+mem[51738] = 5209
+mem[44372] = 408
+mask = 0XX0111X01001X00011000101X0X00100010
+mem[42157] = 28376452
+mem[28513] = 51126906
+mem[43084] = 5419180
+mem[1997] = 54636
+mem[55504] = 3986
+mem[53253] = 14463148
+mask = X1110101X1000101100XX010010101110100
+mem[42226] = 3486504
+mem[54837] = 3033
+mem[15314] = 2651212
+mask = 0111001X010X110000X0110100110001X001
+mem[19828] = 38571
+mem[55362] = 120
+mem[41125] = 297069
+mem[63867] = 760277
+mem[22858] = 1756
+mem[54703] = 2820113
+mask = 0011X10101001101X0101X0110X0X0XX1111
+mem[56317] = 14975
+mem[60301] = 27507
+mem[17408] = 929
+mem[30115] = 7362
+mem[51269] = 13459
+mem[4803] = 162982952
+mask = 0111X1110100110100100110X1X0100011X1
+mem[2066] = 1018
+mem[9704] = 3359
+mem[17252] = 1200
+mem[11567] = 452882913
+mem[55807] = 420485632
+mask = 01011001110010111X011101XX1001XX1100
+mem[5641] = 7642797
+mem[18280] = 394199
+mem[55988] = 3777121
+mem[16857] = 75304
+mem[31220] = 17483158
+mask = X1011X01010100X110010000X00000101100
+mem[6958] = 73282287
+mem[6856] = 10312
+mem[1997] = 225131
+mem[36291] = 3200306
+mem[53139] = 6364
+mem[52857] = 488
+mask = 0X111100010X1X01001X010110X1X0111000
+mem[32210] = 44165292
+mem[61837] = 742353
+mem[47689] = 217901
+mask = 1111X10101001101X01111001X011000X111
+mem[1600] = 5283945
+mem[31412] = 227843745
+mem[3623] = 4853
+mem[21537] = 390
+mem[4405] = 1966
+mem[20470] = 18461
+mem[11567] = 393918381
+mask = 011001XX0X00X101X0X010100X0100111110
+mem[11528] = 1832756
+mem[43104] = 3039
+mem[21774] = 17789
+mem[47052] = 55655944
+mem[8626] = 3587
+mem[19085] = 735520
+mem[33906] = 1155
+mask = 1X0111000100X0011001X100101XX100101X
+mem[22097] = 46921
+mem[44609] = 12686579
+mem[37643] = 642
+mask = 0X001111010011X00XXX1010110000101011
+mem[54063] = 68442463
+mem[40578] = 7777
+mem[42404] = 355257
+mem[35709] = 440
+mem[61541] = 256096
+mask = 01001101011XX1X1101110001001X0000001
+mem[3584] = 16367
+mem[34903] = 7097
+mem[15295] = 238225
+mask = 00011011X1X0X001011XX110001101010001
+mem[47295] = 354843
+mem[23995] = 2140
+mem[57817] = 5421
+mem[41082] = 1355669
+mask = 1111X10101001X01X00XX01X1X1101X111X1
+mem[47377] = 172432
+mem[33686] = 52658909
+mask = 00X101X1010X1X000X1X01011101010X100X
+mem[60202] = 123593
+mem[46408] = 224836575
+mem[32157] = 8489804
+mem[30035] = 833772
+mem[10370] = 115684
+mask = 0X110000X1001XX100X01101110000010100
+mem[20388] = 32592482
+mem[53340] = 1787
+mem[55220] = 59958
+mem[6882] = 1363889
+mask = X00X010X01011XXXX0X101111100X1000001
+mem[56171] = 14491218
+mem[6723] = 143479
+mem[3167] = 466068
+mask = 1111110101X01XX110X11X00101000000101
+mem[17959] = 37575
+mem[64234] = 28252682
+mem[49216] = 434
+mask = 01111111X10011010010111X10X1001X0X0X
+mem[30726] = 5341
+mem[15854] = 1712
+mem[28248] = 492
+mask = 01011011X10X1101X11X1XX0X000X01001X0
+mem[49829] = 780701
+mem[9292] = 2918293
+mem[25072] = 247151
+mask = 0101100X01XX1101011XXX010010X1111001
+mem[19232] = 8569
+mem[54272] = 75036
+mem[54165] = 5018
+mem[31355] = 75073
+mem[9949] = 577427
+mem[30208] = 7439
+mask = 1X11XX01XX001X0110001010100001011000
+mem[9223] = 278171
+mem[14010] = 7098
+mask = 011111010X00110110X1XX00011X00000111
+mem[52261] = 52124331
+mem[39202] = 206235
+mem[45806] = 927
+mask = 0100X101X1X1XX0110X110001000X1000X11
+mem[58118] = 560
+mem[33171] = 204326670
+mem[51319] = 67953886
+mem[51237] = 10958
+mem[56614] = 7267273
+mask = 1XX0XX000101101X10X1X110100100001101
+mem[43771] = 2817
+mem[27887] = 274574
+mem[63850] = 107
+mask = X010111101001100011000XX1011X1101X10
+mem[30088] = 63233721
+mem[30726] = 605150
+mem[56614] = 48162
+mem[11271] = 2038084
+mask = X0X10110X100110100101X1111000001X10X
+mem[24920] = 989
+mem[59782] = 151549707
+mem[22082] = 7033941
+mem[22671] = 330574441
+mem[5252] = 1859
+mask = 0011110001X01100001XXX10111101X1X001
+mem[12192] = 47533
+mem[18902] = 118818
+mem[24826] = 19391580
+mem[3918] = 710
+mem[53370] = 19365460
+mem[49665] = 14466588
+mask = 0X11X101010011011011X110101100X001X0
+mem[23829] = 31936270
+mem[15854] = 13849536
+mem[29208] = 3999149
+mem[37128] = 13918
+mem[3328] = 259186933
+mask = 1X1X1X01010X110110111X000X0001000100
+mem[2629] = 55317
+mem[49216] = 881
+mem[40870] = 1619590
+mask = X1001XX10101000110011X0010X00110001X
+mem[3918] = 16125795
+mem[2919] = 13852
+mem[18470] = 7583882
+mask = 001101000X0X110XX0101011110X01001001
+mem[51858] = 157
+mem[4120] = 103247344
+mem[13914] = 423240
+mem[61736] = 159857
+mask = 0X011011010X1X0101111110XX0010XX00X1
+mem[61289] = 75040
+mem[43263] = 107031474
+mask = 11111X010100110X0X0010X011X100011101
+mem[29419] = 4825
+mem[16760] = 16715
+mem[42563] = 1981
+mem[40827] = 616757
+mem[51565] = 353
+mask = 010X10X00X00110X111X110X000XX0111101
+mem[2967] = 442177
+mem[18301] = 37578
+mem[56358] = 682
+mem[39237] = 59986049
+mem[2456] = 108546
+mask = 00100X0XX10011X1XX101X111100000XX001
+mem[6578] = 469499
+mem[60824] = 1460
+mem[50713] = 7725506

day_14.py

@@ -0,0 +1,212 @@
+"""
+https://adventofcode.com/2020/day/14
+
+1.
+Execute the initialization program. What is the sum of all values left in memory after it completes?
+
+2. Execute the initialization program using an emulator for a version 2 decoder chip.
+What is the sum of all values left in memory after it completes?
+"""
+from abc import ABC, abstractmethod
+import re
+from copy import deepcopy
+
+filename = "data/input_14.txt"
+
+
+class Command(ABC):
+    def __init__(self, data):
+        self.parse(data)
+
+    @abstractmethod
+    def parse(self):
+        pass
+
+    @abstractmethod
+    def execute(self, executor):
+        pass
+
+
+class SetMaskCommand(Command):
+    def parse(self, data):
+        self.mask = data[(data.find("=") + 1):].strip()
+
+    def execute(self, executor):
+        executor.set_mask(self.mask)
+
+
+class WriteToMemory(Command):
+    def parse(self, data):
+        self.key = int(re.compile(r"mem\[(\d+)\]").search(data).group(1))
+        self.value = int(re.compile(r"= (\d+)$").search(data).group(1))
+
+    def execute(self, executor):
+        executor.write_to_memory(self.key, self.value)
+
+
+class Executor:
+    mask_length = 36
+
+    def __init__(self, lines):
+        self.commands = [self.parse_command(line) for line in lines]
+        self.mask = None
+        self.memory = {}
+
+    def set_mask(self, mask):
+        self.mask = mask
+
+    @staticmethod
+    def mask_bit(bit, mask_char):
+        if mask_char == "X":
+            return bit
+        elif mask_char in ["0", "1"]:
+            return mask_char
+        else:
+            raise ValueError("Unknown mask_char %s" % mask_char)
+
+    def apply_mask(self, value):
+        value_36_bits = (("0" * self.mask_length) + bin(value)[2:])[-self.mask_length:]
+        masked_value = "".join([self.mask_bit(bit, m) for (bit, m) in zip(value_36_bits, self.mask)])
+        masked_value = int(masked_value, 2)
+        return masked_value
+
+    def write_to_memory(self, key, value):
+        self.memory[key] = self.apply_mask(value)
+
+    @staticmethod
+    def parse_command(line):
+        if line.startswith("mask"):
+            command = SetMaskCommand(line)
+        elif line.startswith("mem"):
+            command = WriteToMemory(line)
+        else:
+            raise ValueError("Unknown command: %s!" % line)
+        return command
+
+    def execute_all(self):
+        for command in self.commands:
+            command.execute(self)
+
+
+def part1():
+    with open(filename) as fp:
+        lines = [line.strip("\n") for line in fp]
+    executor = Executor(lines)
+    executor.execute_all()
+    print("Answer: %d" % (sum(executor.memory.values())))
+
+
+class Memory:
+    def __init__(self, address_length):
+        self.address_length = address_length
+        self.memory = {}
+
+    def set_minus(self, address1, address2):
+        """ returns set: address1 - address2 """
+        assert len(address1) == len(address2)
+        address1 = list(address1)
+        address2 = list(address2)
+        # Replace "X" in address2 by values in address1. This subset of address2 can only intersect with address1
+        address2 = [address2[i] if (address2[i] in ["0", "1"]) else address1[i] for i in range(self.address_length)]
+        intersect = all([
+            (address1[i] == address2[i]) or (address1[i] == "X") for i in range(self.address_length)
+            if (address2[i] in ["0", "1"])
+        ])
+        if not intersect:
+            return ["".join(address1)]
+        temp = [i for i in range(self.address_length) if (address1[i] == "X") and (address2[i] in ["0", "1"])]
+        if len(temp) == 0:  # address2 covers address1 totally
+            return [""]  # empty set
+        first_X_in_1_not_in_2 = min(temp)
+        # Set first "X" address1 to opposite of 0/1 value in address2
+        not_intersecting1 = deepcopy(address1)
+        not_intersecting1[first_X_in_1_not_in_2] = str(abs(int(address2[first_X_in_1_not_in_2]) - 1))  # 0->1 and 1->0
+        remainder1 = deepcopy(address1)
+        # In other branch set it equal. For this branch, use recursion to find out set minus
+        remainder1[first_X_in_1_not_in_2] = address2[first_X_in_1_not_in_2]
+        return ["".join(not_intersecting1)] + self.set_minus(remainder1, address2)
+
+    def write(self, address, value):
+        addresses_in_memory = list(self.memory.keys())
+        set_minuses = [self.set_minus(a, address) for a in addresses_in_memory]
+        # Remove empty sets "":
+        set_minuses = [[a for a in s if a != ""] for s in set_minuses]
+        # Update existing memory:
+        for i, s in enumerate(set_minuses):
+            # Remove old address: value
+            val = self.memory[addresses_in_memory[i]]
+            del self.memory[addresses_in_memory[i]]
+            # Rewrite val to address space not intersecting with new value
+            for a in s:
+                self.memory[a] = val
+        # Insert new overwriting value
+        self.memory[address] = value
+
+    def get_address_sum(self, address):
+        number_of_addresses = 2**(address.count("X"))
+        return number_of_addresses * self.memory[address]
+
+    def get_sum(self):
+        return sum([self.get_address_sum(a) for a in self.memory.keys()])
+
+
+class Executor2:
+    mask_length = 36
+
+    def __init__(self, lines):
+        self.commands = [self.parse_command(line) for line in lines]
+        self.mask = None
+        self.memory = Memory(address_length=36)
+
+    def set_mask(self, mask):
+        self.mask = mask
+
+    @staticmethod
+    def mask_bit(bit, mask_char):
+        if mask_char == "0":
+            return bit
+        elif mask_char in ["1", "X"]:
+            return mask_char
+        else:
+            raise ValueError("Unknown mask_char %s" % mask_char)
+
+    def apply_mask(self, value):
+        value_36_bits = (("0" * self.mask_length) + bin(value)[2:])[-self.mask_length:]
+        masked_value = "".join([self.mask_bit(bit, m) for (bit, m) in zip(value_36_bits, self.mask)])
+        return masked_value
+
+    def write_to_memory(self, address, value):
+        masked_address = self.apply_mask(address)
+        self.memory.write(masked_address, value)
+
+    @staticmethod
+    def parse_command(line):
+        if line.startswith("mask"):
+            command = SetMaskCommand(line)
+        elif line.startswith("mem"):
+            command = WriteToMemory(line)
+        else:
+            raise ValueError("Unknown command: %s!" % line)
+        return command
+
+    def execute_all(self):
+        for i, command in enumerate(self.commands):
+            print(i)
+            command.execute(self)
+
+    def get_memory_sum(self):
+        return self.memory.get_sum()
+
+
+def part2():
+    with open(filename) as fp:
+        lines = [line.strip("\n") for line in fp]
+    executor = Executor2(lines)
+    executor.execute_all()
+    print("Answer: %d" % executor.get_memory_sum())
+
+
+if __name__ == "__main__":
+    part1()
+    print("*****")
+    part2()