Day 6: Probably a Fire Hazard

advent-of-code.org

@@ -2634,3 +2634,456 @@ How many strings are nice under these new rules?
 
 #+RESULTS[714e53b40cf4a27435a59eafbd8c488cb05bd539]:
 : 55
+
+* Day 6: Probably a Fire Hazard
+
+Because your neighbors keep defeating you in the holiday house
+decorating contest year after year, you've decided to deploy one
+million lights in a 1000x1000 grid.
+
+Furthermore, because you've been especially nice this year, Santa has
+mailed you instructions on how to display the ideal lighting
+configuration.
+
+Lights in your grid are numbered from 0 to 999 in each direction; the
+lights at each corner are at =0,0=, =0,999=, =999,999=, and =999,0=.
+The instructions include whether to =turn on=, =turn off=, or =toggle=
+various inclusive ranges given as coordinate pairs. Each coordinate
+pair represents opposite corners of a rectangle, inclusive; a
+coordinate pair like =0,0= through =2,2= therefore refers to 9 lights
+in a 3x3 square. The lights all start turned off.
+
+To defeat your neighbors this year, all you have to do is set up your
+lights by doing the instructions Santa sent you in order.
+
+For example:
+
+- =turn on 0,0 through 999,999= would turn on (or leave on) every
+  light.
+- =toggle 0,0 through 999,0= would toggle the first line of 1000
+  lights, turning off the ones that were on, and turning on the ones
+  that were off.
+- =turn off 499,499 through 500,500= would turn off (or leave off) the
+  middle four lights.
+
+After following the instructions, how many lights are lit?
+
+----------------------------------------------------------------------
+
+:HIDDEN:
+#+name: 6-input
+#+BEGIN_EXAMPLE
+  turn on 887,9 through 959,629
+  turn on 454,398 through 844,448
+  turn off 539,243 through 559,965
+  turn off 370,819 through 676,868
+  turn off 145,40 through 370,997
+  turn off 301,3 through 808,453
+  turn on 351,678 through 951,908
+  toggle 720,196 through 897,994
+  toggle 831,394 through 904,860
+  toggle 753,664 through 970,926
+  turn off 150,300 through 213,740
+  turn on 141,242 through 932,871
+  toggle 294,259 through 474,326
+  toggle 678,333 through 752,957
+  toggle 393,804 through 510,976
+  turn off 6,964 through 411,976
+  turn off 33,572 through 978,590
+  turn on 579,693 through 650,978
+  turn on 150,20 through 652,719
+  turn off 782,143 through 808,802
+  turn off 240,377 through 761,468
+  turn off 899,828 through 958,967
+  turn on 613,565 through 952,659
+  turn on 295,36 through 964,978
+  toggle 846,296 through 969,528
+  turn off 211,254 through 529,491
+  turn off 231,594 through 406,794
+  turn off 169,791 through 758,942
+  turn on 955,440 through 980,477
+  toggle 944,498 through 995,928
+  turn on 519,391 through 605,718
+  toggle 521,303 through 617,366
+  turn off 524,349 through 694,791
+  toggle 391,87 through 499,792
+  toggle 562,527 through 668,935
+  turn off 68,358 through 857,453
+  toggle 815,811 through 889,828
+  turn off 666,61 through 768,87
+  turn on 27,501 through 921,952
+  turn on 953,102 through 983,471
+  turn on 277,552 through 451,723
+  turn off 64,253 through 655,960
+  turn on 47,485 through 734,977
+  turn off 59,119 through 699,734
+  toggle 407,898 through 493,955
+  toggle 912,966 through 949,991
+  turn on 479,990 through 895,990
+  toggle 390,589 through 869,766
+  toggle 593,903 through 926,943
+  toggle 358,439 through 870,528
+  turn off 649,410 through 652,875
+  turn on 629,834 through 712,895
+  toggle 254,555 through 770,901
+  toggle 641,832 through 947,850
+  turn on 268,448 through 743,777
+  turn off 512,123 through 625,874
+  turn off 498,262 through 930,811
+  turn off 835,158 through 886,242
+  toggle 546,310 through 607,773
+  turn on 501,505 through 896,909
+  turn off 666,796 through 817,924
+  toggle 987,789 through 993,809
+  toggle 745,8 through 860,693
+  toggle 181,983 through 731,988
+  turn on 826,174 through 924,883
+  turn on 239,228 through 843,993
+  turn on 205,613 through 891,667
+  toggle 867,873 through 984,896
+  turn on 628,251 through 677,681
+  toggle 276,956 through 631,964
+  turn on 78,358 through 974,713
+  turn on 521,360 through 773,597
+  turn off 963,52 through 979,502
+  turn on 117,151 through 934,622
+  toggle 237,91 through 528,164
+  turn on 944,269 through 975,453
+  toggle 979,460 through 988,964
+  turn off 440,254 through 681,507
+  toggle 347,100 through 896,785
+  turn off 329,592 through 369,985
+  turn on 931,960 through 979,985
+  toggle 703,3 through 776,36
+  toggle 798,120 through 908,550
+  turn off 186,605 through 914,709
+  turn off 921,725 through 979,956
+  toggle 167,34 through 735,249
+  turn on 726,781 through 987,936
+  toggle 720,336 through 847,756
+  turn on 171,630 through 656,769
+  turn off 417,276 through 751,500
+  toggle 559,485 through 584,534
+  turn on 568,629 through 690,873
+  toggle 248,712 through 277,988
+  toggle 345,594 through 812,723
+  turn off 800,108 through 834,618
+  turn off 967,439 through 986,869
+  turn on 842,209 through 955,529
+  turn on 132,653 through 357,696
+  turn on 817,38 through 973,662
+  turn off 569,816 through 721,861
+  turn on 568,429 through 945,724
+  turn on 77,458 through 844,685
+  turn off 138,78 through 498,851
+  turn on 136,21 through 252,986
+  turn off 2,460 through 863,472
+  turn on 172,81 through 839,332
+  turn on 123,216 through 703,384
+  turn off 879,644 through 944,887
+  toggle 227,491 through 504,793
+  toggle 580,418 through 741,479
+  toggle 65,276 through 414,299
+  toggle 482,486 through 838,931
+  turn off 557,768 through 950,927
+  turn off 615,617 through 955,864
+  turn on 859,886 through 923,919
+  turn on 391,330 through 499,971
+  toggle 521,835 through 613,847
+  turn on 822,787 through 989,847
+  turn on 192,142 through 357,846
+  turn off 564,945 through 985,945
+  turn off 479,361 through 703,799
+  toggle 56,481 through 489,978
+  turn off 632,991 through 774,998
+  toggle 723,526 through 945,792
+  turn on 344,149 through 441,640
+  toggle 568,927 through 624,952
+  turn on 621,784 through 970,788
+  toggle 665,783 through 795,981
+  toggle 386,610 through 817,730
+  toggle 440,399 through 734,417
+  toggle 939,201 through 978,803
+  turn off 395,883 through 554,929
+  turn on 340,309 through 637,561
+  turn off 875,147 through 946,481
+  turn off 945,837 through 957,922
+  turn off 429,982 through 691,991
+  toggle 227,137 through 439,822
+  toggle 4,848 through 7,932
+  turn off 545,146 through 756,943
+  turn on 763,863 through 937,994
+  turn on 232,94 through 404,502
+  turn off 742,254 through 930,512
+  turn on 91,931 through 101,942
+  toggle 585,106 through 651,425
+  turn on 506,700 through 567,960
+  turn off 548,44 through 718,352
+  turn off 194,827 through 673,859
+  turn off 6,645 through 509,764
+  turn off 13,230 through 821,361
+  turn on 734,629 through 919,631
+  toggle 788,552 through 957,972
+  toggle 244,747 through 849,773
+  turn off 162,553 through 276,887
+  turn off 569,577 through 587,604
+  turn off 799,482 through 854,956
+  turn on 744,535 through 909,802
+  toggle 330,641 through 396,986
+  turn off 927,458 through 966,564
+  toggle 984,486 through 986,913
+  toggle 519,682 through 632,708
+  turn on 984,977 through 989,986
+  toggle 766,423 through 934,495
+  turn on 17,509 through 947,718
+  turn on 413,783 through 631,903
+  turn on 482,370 through 493,688
+  turn on 433,859 through 628,938
+  turn off 769,549 through 945,810
+  turn on 178,853 through 539,941
+  turn off 203,251 through 692,433
+  turn off 525,638 through 955,794
+  turn on 169,70 through 764,939
+  toggle 59,352 through 896,404
+  toggle 143,245 through 707,320
+  turn off 103,35 through 160,949
+  toggle 496,24 through 669,507
+  turn off 581,847 through 847,903
+  turn on 689,153 through 733,562
+  turn on 821,487 through 839,699
+  turn on 837,627 through 978,723
+  toggle 96,748 through 973,753
+  toggle 99,818 through 609,995
+  turn on 731,193 through 756,509
+  turn off 622,55 through 813,365
+  turn on 456,490 through 576,548
+  turn on 48,421 through 163,674
+  turn off 853,861 through 924,964
+  turn off 59,963 through 556,987
+  turn on 458,710 through 688,847
+  toggle 12,484 through 878,562
+  turn off 241,964 through 799,983
+  turn off 434,299 through 845,772
+  toggle 896,725 through 956,847
+  turn on 740,289 through 784,345
+  turn off 395,840 through 822,845
+  turn on 955,224 through 996,953
+  turn off 710,186 through 957,722
+  turn off 485,949 through 869,985
+  turn on 848,209 through 975,376
+  toggle 221,241 through 906,384
+  turn on 588,49 through 927,496
+  turn on 273,332 through 735,725
+  turn on 505,962 through 895,962
+  toggle 820,112 through 923,143
+  turn on 919,792 through 978,982
+  toggle 489,461 through 910,737
+  turn off 202,642 through 638,940
+  turn off 708,953 through 970,960
+  toggle 437,291 through 546,381
+  turn on 409,358 through 837,479
+  turn off 756,279 through 870,943
+  turn off 154,657 through 375,703
+  turn off 524,622 through 995,779
+  toggle 514,221 through 651,850
+  toggle 808,464 through 886,646
+  toggle 483,537 through 739,840
+  toggle 654,769 through 831,825
+  turn off 326,37 through 631,69
+  turn off 590,570 through 926,656
+  turn off 881,913 through 911,998
+  turn on 996,102 through 998,616
+  turn off 677,503 through 828,563
+  turn on 860,251 through 877,441
+  turn off 964,100 through 982,377
+  toggle 888,403 through 961,597
+  turn off 632,240 through 938,968
+  toggle 731,176 through 932,413
+  turn on 5,498 through 203,835
+  turn on 819,352 through 929,855
+  toggle 393,813 through 832,816
+  toggle 725,689 through 967,888
+  turn on 968,950 through 969,983
+  turn off 152,628 through 582,896
+  turn off 165,844 through 459,935
+  turn off 882,741 through 974,786
+  turn off 283,179 through 731,899
+  toggle 197,366 through 682,445
+  turn on 106,309 through 120,813
+  toggle 950,387 through 967,782
+  turn off 274,603 through 383,759
+  turn off 155,665 through 284,787
+  toggle 551,871 through 860,962
+  turn off 30,826 through 598,892
+  toggle 76,552 through 977,888
+  turn on 938,180 through 994,997
+  toggle 62,381 through 993,656
+  toggle 625,861 through 921,941
+  turn on 685,311 through 872,521
+  turn on 124,934 through 530,962
+  turn on 606,379 through 961,867
+  turn off 792,735 through 946,783
+  turn on 417,480 through 860,598
+  toggle 178,91 through 481,887
+  turn off 23,935 through 833,962
+  toggle 317,14 through 793,425
+  turn on 986,89 through 999,613
+  turn off 359,201 through 560,554
+  turn off 729,494 through 942,626
+  turn on 204,143 through 876,610
+  toggle 474,97 through 636,542
+  turn off 902,924 through 976,973
+  turn off 389,442 through 824,638
+  turn off 622,863 through 798,863
+  turn on 840,622 through 978,920
+  toggle 567,374 through 925,439
+  turn off 643,319 through 935,662
+  toggle 185,42 through 294,810
+  turn on 47,124 through 598,880
+  toggle 828,303 through 979,770
+  turn off 174,272 through 280,311
+  turn off 540,50 through 880,212
+  turn on 141,994 through 221,998
+  turn on 476,695 through 483,901
+  turn on 960,216 through 972,502
+  toggle 752,335 through 957,733
+  turn off 419,713 through 537,998
+  toggle 772,846 through 994,888
+  turn on 881,159 through 902,312
+  turn off 537,651 through 641,816
+  toggle 561,947 through 638,965
+  turn on 368,458 through 437,612
+  turn on 290,149 through 705,919
+  turn on 711,918 through 974,945
+  toggle 916,242 through 926,786
+  toggle 522,272 through 773,314
+  turn on 432,897 through 440,954
+  turn off 132,169 through 775,380
+  toggle 52,205 through 693,747
+  toggle 926,309 through 976,669
+  turn off 838,342 through 938,444
+  turn on 144,431 through 260,951
+  toggle 780,318 through 975,495
+  turn off 185,412 through 796,541
+  turn on 879,548 through 892,860
+  turn on 294,132 through 460,338
+  turn on 823,500 through 899,529
+  turn off 225,603 through 483,920
+  toggle 717,493 through 930,875
+  toggle 534,948 through 599,968
+  turn on 522,730 through 968,950
+  turn off 102,229 through 674,529
+#+END_EXAMPLE
+:END:
+
+#+BEGIN_SRC emacs-lisp :var input=6-input :exports both
+  (defun day6/make-light ()
+    nil)
+
+  (defun day6/turn-on-light (light)
+    t)
+
+  (defun day6/turn-off-light (light)
+    nil)
+
+  (defun day6/toggle-light (light)
+    (not light))
+
+  (defun day6/lit? (light)
+    light)
+
+  (defun day6/make-grid (size)
+    (let ((table (make-hash-table :size (* size size))))
+      (-each (number-sequence 0 (- (* size size) 1))
+        (lambda (pos) (puthash pos (day6/make-light) table)))
+      (cons size
+            table)))
+
+  (defun day6/grid-size (grid)
+    (car grid))
+
+  (defun day6/grid-table (grid)
+    (cdr grid))
+
+  (defun day6/grid-lights (grid)
+    (hash-table-values (day6/grid-table grid)))
+
+  (defun day6/grid-location (grid x y)
+    (+ x (* y (day6/grid-size grid))))
+
+  (ert-deftest day6/grid-location ()
+    (should (eq 99 (let ((grid (day6/make-grid 100)))
+                     (day6/grid-location grid 99 0))))
+    (should (eq 100 (let ((grid (day6/make-grid 100)))
+                      (day6/grid-location grid 0 1)))))
+
+  (defun day6/grid-light (grid location)
+    (gethash location (day6/grid-table grid)))
+
+  (defun day6/grid-do (grid fun location)
+    (puthash location
+             (funcall fun (day6/grid-light grid location))
+             (day6/grid-table grid)))
+
+  (defun day6/change-range (grid light-fun x1 y1 x2 y2)
+    (loop for x from x1 to x2
+          do (loop for y from y1 to y2
+                   do (let* ((location (day6/grid-location grid x y)))
+                        (day6/grid-do grid light-fun location)))))
+
+  (defun day6/lit-count (grid)
+    (length (-filter #'day6/lit? (day6/grid-lights grid))))
+
+  (ert-deftest day6/lit-count ()
+    (should (eq 1000000
+                (let ((grid (day6/make-grid 1000)))
+                  (day6/change-range grid #'day6/turn-on-light
+                                     0 0 999 999)
+                  (day6/lit-count grid))))
+    (should (eq 4
+                (let ((grid (day6/make-grid 1000)))
+                  (day6/change-range grid #'day6/turn-on-light
+                                     499 499 500 500)
+                  (day6/lit-count grid)))))
+
+  (defun day6/parse-instruction (instruction)
+    (if (string-match (concat "\\(turn \\(on\\|off\\)\\|toggle\\) "
+                              "\\([0-9]+\\),\\([0-9]+\\)"
+                              " through "
+                              "\\([0-9]+\\),\\([0-9]+\\)")
+                      instruction)
+        (list (cond ((string-equal "turn on" (match-string 1 instruction))
+                     #'day6/turn-on-light)
+                    ((string-equal "turn off" (match-string 1 instruction))
+                     #'day6/turn-off-light)
+                    ((string-equal "toggle" (match-string 1 instruction))
+                     #'day6/toggle-light))
+              (string-to-int (match-string 3 instruction))
+              (string-to-int (match-string 4 instruction))
+              (string-to-int (match-string 5 instruction))
+              (string-to-int (match-string 6 instruction)))))
+
+  (ert-deftest day6/parse-instruction ()
+    (should (equal '(day6/turn-on-light 887 9 959 629)
+                   (day6/parse-instruction "turn on 887,9 through 959,629")))
+    (should (equal '(day6/turn-off-light 539 243 559 965)
+                   (day6/parse-instruction "turn off 539,243 through 559,965")))
+    (should (equal '(day6/toggle-light 720 196 897 994)
+                   (day6/parse-instruction "toggle 720,196 through 897,994"))))
+
+  (defun day6/run-instruction (grid instruction)
+    (let ((parsed-instruction (day6/parse-instruction instruction)))
+      (eval (append '(day6/change-range grid)
+                    `(',(first parsed-instruction))
+                    (rest parsed-instruction)))))
+
+  (let ((grid (day6/make-grid 1000)))
+    (-each (split-string input "\n" t)
+      (apply-partially 'day6/run-instruction grid))
+    (day6/lit-count grid))
+#+END_SRC
+
+#+RESULTS[2e528f53a45a3c7e0dcc549d5ac69918287ddd6e]:
+: 377891
+
+