diff options
Diffstat (limited to 'day3.zig')
| -rw-r--r-- | day3.zig | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/day3.zig b/day3.zig new file mode 100644 index 0000000..b078f76 --- /dev/null +++ b/day3.zig @@ -0,0 +1,235 @@ +const std = @import("std"); +const Setup = @import("common.zig").Setup; + +pub fn main() !void { + // var setup = try Setup.get(); + // defer setup.deinit(); + try std.fmt.format(std.io.getStdOut().writer(), "day 3: {}\n", .{try solve(std.heap.page_allocator, input2)}); +} + +const Grid = struct { + buf: []const u8, + width: usize, + height: usize, + + fn init(input: []const u8) !Grid { + const height = std.mem.count(u8, input, "\n")+1; + const width = std.mem.indexOfScalar(u8, input, '\n') orelse return error.NoNewlines; + return .{ + .buf = input, + .width = width, + .height = height, + }; + } + fn get(self: Grid, x: usize, y: usize) ?u8 { + if (x >= self.width) return null; + if (y >= self.height) return null; + // width +1 becuase the buffer still has newlines in it + return self.buf[@intCast((self.width+1) * y + x)]; + } +}; + +fn solve(a: std.mem.Allocator, input: []const u8) !u32 { + var spanBuf = std.ArrayList(u8).init(a); + defer spanBuf.deinit(); + const grid = try Grid.init(input); + var sum: u32 = 0; + for (0..grid.height) |y| { + spanBuf.clearRetainingCapacity(); + for (0..grid.width) |x| { + const ch = grid.get(x, y) orelse return error.IndexError; + if (std.ascii.isDigit(ch)) { + try spanBuf.append(ch); + } + // end-of-span, either hit a non-digit or end of line + if ((!std.ascii.isDigit(ch) or (x==grid.width-1)) and spanBuf.items.len > 0) { + const num = try std.fmt.parseInt(u32, spanBuf.items, 10); + const num_len = spanBuf.items.len; + spanBuf.clearRetainingCapacity(); + // now check all the surrounding positions including diagonals, for non-digits and points + const search_x_end = x; + const search_x_start = std.math.sub(usize, search_x_end, (num_len+1)) catch search_x_end-num_len; + const is_part: bool = br: for (search_x_start..(search_x_end)+1) |x_p| { + const search_y_start = std.math.sub(usize, y, 1) catch y; + const search_y_end = y+1; + for (search_y_start..(search_y_end+1)) |y_p| { + if (grid.get(x_p, y_p)) |adj| { + if (!std.ascii.isDigit(adj) and adj != '.') { + //std.log.info("found symbol {c} next to num {}", .{adj, num}); + break :br true; + } + } + } + } else { + //std.log.info("no symbol next to num {}", .{num}); + break :br false; + }; + if (is_part) { + sum += num; + } + } + } + } + return sum; +} + + + +test { + const input = + \\467..114.. + \\...*...... + \\..35..633. + \\......#... + \\617*...... + \\.....+.58. + \\..592..... + \\......755. + \\...$.*.... + \\.664.598.. + ; + try std.testing.expectEqual(@as(u32, 4361), try solve(std.testing.allocator, input)); +} + +const input2 = +\\.......497...........................858...923...128..................227..801........487.....664........................................... +\\436........765..............140.......+....................859.............*.........+.................960........668....................... +\\...*982...........=..........=....203......266.263...375*....=...402....691..-....................*..........575....................13...... +\\.............114...588...............*............*......631........*.......952...463..14.......661..........=...706......*333.........595.. +\\...194.........*..............743...917.&......375.....................................*...............544*.......*....664.................. +\\...*.....807..452....81..........*......969..#......309*................/....873....941...828.197..........427.728...............566...13... +\\.243........*.....80.......329....470.......145.475.....111........*659..259....+........*....%........569..............%.....*....*....*... +\\.........130......*....385*............123......................199.......................640.....463..%.........978....920...266..380.83... +\\.....323........870.........+...........$.........466......453........................297...........*............*.......................... +\\........*.=..............588.....*786......$.........*........*.......390*.....886...*....227...728..852.......606....*863.......916..396... +\\.....538...287................301........133.....539..........33.537......466..$...793..+..........*...............218.....721........*..... +\\...............986.........=.......................................*...%...............222..-.......701.271...............#.........437..... +\\......*3.........*.626.68...419...740...........................806...976.......875.........174..............735.............=488........... +\\...790.........487....*................./532..13............................*....-.....503..........*11..734..........978.19......622....... +\\...................&....712.68=.619+.........*.......................863...596.....2.....*.......160.....+...&659........*.........-....-757 +\\437*.......#........520...*..........304....568.974.255.318.183.........*.......&.....675......................................849.......... +\\....161.....687.710.....854.............*.......*......*....&...441......891.....476..........616.......$........235..434.880...*..673+..... +\\..................*...............683.....800.120..............*....807..................................707.....*....-....*...74........562 +\\....@...#988...487..#685..........-......*..............251.146.............................142@....74...........398....769..........238*... +\\....848....../................-.$.....662.........773..*...........895.......591...........................233.............................. +\\797.........611..........@.186...429..........304*....468.....554....*..........*...960......82.......*810...+.534..660....645...313./...... +\\......239..............509...............720*......................844..939=..508......*...........401............*.......*.......*...649... +\\........=........158.......$.....=...........200......409....982.....................46................126.....517....303.647.660........... +\\...530....=......*..........704.69...................*.......*..................@879........589..131.................*........*............. +\\......*..871...672....................611*........415.......283.569.21....842/........-109.&.......*.......157$...719.......679.$........... +\\....664..............664......668.........203....................&...%............................14..................427.......833..484.... +\\....................*........*.......434.......796...........65............................................-479.126..*..............+....... +\\.....382..........121.....836.........*........@...............*789.......624........350&..........*544............$.6.........882....513... +\\....%.....406.........................848........625...%...88.........382..+..971.................5......*622...........914....*....%....... +\\..............627....816........641..............*.....373./.............*..../...912..651.162........557........901...&.....503.337....59.. +\\...357...........*.........552...*..816..........240......................636.....*...*.....*.............@..993....*....................... +\\......*934....961...=..43..*...324.....@...............726.888....370...........170.805...517........639.389....*..929.................953.. +\\.16...............408.*...94..................................*......&..............................*......../...9........605............... +\\.......571....13......512........591+.......976.......895....489...........751.......474.760.........240.....931............*............... +\\...464../..................608..............*........*................$.94*........................................486.......172............ +\\...*......121........=.....*.......$......909.......583............128........929...................765.............*............+....24.... +\\.............*.......762....230..422..285.....434......................390.....=.....921.................261....#...949.....382...903.*..... +\\............595........................*.......*...................833*..............%.......973..$....@...*.268........506*..........251... +\\967...................................25....234...........................306....281..........=..36..918.432....../406........344...$....... +\\.....700*610.......=...839......917......33......610@................537....=....@............................%........20.402.@.....926..... +\\..............%.768...*....................*...@............93..161.%...............74$......%.........96..298..........%..+............+519 +\\...........925.......586...................264..85...721....*...*.............................371.................822.=..................... +\\...............540...........-....447....................987.....305.............379@.707..............670...397...*..842....552.464........ +\\.....666......*....844....515.......*..............+114..............977...............&...393........*.........$.800...........*........... +\\.....*...647...696..*..............203....................418.....19............522........*.......462................57...786..........561. +\\....691.....$.......756...165.....................596.32...%........#..280.259$..........398..............425.............*....719..796..... +\\.............../.........=........1/..305............*.........451......&..........332.......706............&.......327.841...........*..... +\\.74..........791.............=........+.....................+...-..................+..........*.....................*...............419..371 +\\...*927..........352.......148..........401....459...+....998......$783........@............444..$.......959..106.366....................... +\\............190..........*......385.............*....846......................907.826..585.......447.441..*..*............7......871........ +\\.................142....944....$.................634.............587..@..930..........*......935.....*...819.29.....3......*35.............. +\\......967....415*......................=980.....................%....58.-......317..74......../.....922..............-.207........../....... +\\.........................................................................................................175....................369.233..... +\\.........................+....645.$........%.....620.+429....951......616.................................*............524$................. +\\....799...551*602........920..+....503..654....-...*............*....=......395.........451....263.......897..................370........... +\\......-.......................................409......970....661.............*............+...*....48...................475..$........839.. +\\..97...................../.....@497....%..........446$...*...............533..794.....432-.....167...*.....722...486........*...500...*..... +\\..............459......540.............110................569............&..................#.....................#........785.*.......455.. +\\........815....*...........................*452......./......................365.........929....*978.=................709........+..84...... +\\....427*......466.............608*796..............680......................*......&.........142.....603.................#......621..*...... +\\.........635............@....................302..................296-.....679...801..290..................464..............980......627.... +\\....../.../........%...850.......*108....513*........656...*739........715...............@.......713.......*...................*............ +\\354+..245.......629...........995.....................$..41.....=.....@.....................45..........840......506+...$.....148........... +\\..........995.................................&541............914.510.....950...../...........*53..28...................275........138...... +\\.............*812..665...../.........................101.308..............*......691.482.............*........902.585.......@.......*....... +\\.........../........./...292...............#..........-....*....@307......661..........*.210......135....932%...........992..54..191..931... +\\...400..649...............................504.196.........88........................581.............................743*.............&...... +\\...*.........140..............642....891.............309...............................................695......361..............603........ +\\....170.643#..*.................*....*.......*24.....*....................932.291.....538....461.........*........*..275............&....... +\\.............725......494......23...279...713..../....449............*........*...../...=......*..........434..............785.............. +\\.....991..........946.............................830.........136.439.24...519......289.......408...579........708.650*......*.370.13....410 +\\......*..887........#..688.673.........218......................-...............941....................$.......%.......927.722....*......... +\\....124....*...........*..../....427....*.............312................................................922...........................307.. +\\...........706...16..934..*.......*......608....459..&..........761.....................647..641...........*.............242............*... +\\..5*715..-........+........122.....262........./...........928....%............728..610*......*..502.....222..40.....923..+...........540... +\\.........701.............=..............291...............*.........351.........*............141.%............*.../.....*....725............ +\\..............314.......878....%.......*......=..820*.....988..204.....-.....889......119............797...........395....+.............287. +\\..................671........322....101......257.....733........@.....................=.............*..........544......600.......862....... +\\..421.......582...%..............................484...............565.....+...831...........695...384.#...592.=............240....../.904.. +\\....*..........*........570...........&....=........*629......717&.*.......93......726../961....*......535..*........767../......715....*... +\\....439.....630............../..%...615...912......................777............*..............602.........567..3........107....$..77..... +\\....................914.....3...2.=.............763...&885......................185....182.......................*......-......+............ +\\...372...383........*..............60.............*............&..38.681...............*.....459....../........117...504......358..480-..... +\\............+.990..33...........................834.......@..33......................494....*........181.66+................................ +\\...............*......*...492..............176..........857...........376.315................954.....................*982.......763......... +\\329=..........179....245...*...61...........*...*................%......+....*.....352*509.........952#..69..620..423.............*......... +\\.........................131.....*17......191.33.306...../.....144..503......491.............................................298...415...... +\\...................$...................................426.........*...............526.669.....&498..698...$............447.....+........... +\\.............575...142.617......890..............%...............212..730.519.971..&......*384.........@....18.219.........*................ +\\.......*537..*.........*........*.........677...587..407...120*........./....*...................................+......334..........700.... +\\....944......636..848........743.....388..*....................109..........................................................540.40..*....... +\\.................*....596............*....155..324...820.520.................=...............443...94...........621.276......*..+..910...... +\\...............276.....-.........376...........*........*....................739......368....=..............428....*......434..........878.. +\\932....28.....................-..=....207......959....................289.........196.*........................*...............-.......=.... +\\...*........................172....#.#.....688.........25..944...725...&............*..110.....148...426.483..771../932......800............ +\\.947............................457....931*.............-....*...#.......834......721.........*.........*.............................477... +\\.....*491......*.........*114.................191.....$...213........909*...................194............633....%...792..605.633...#...... +\\.............108......611.....+719...........*.....696........865...............120................=724...%....950.../......*...../......... +\\...320............*.................260/...121.........338...*........719.180.........516.....*.............................649............. +\\.....#...643.......941......*160......................*......140...94....*...............*..39.789................*......&.........81...597. +\\............*..135.......532.................%90...608............*............+515....743.............+...194.993.669..259..+.............. +\\.....%....948.....*............262..695.712....................623.....*...................473........602...*...............83......679..... +\\..259.............447.............%.*...............363.............105...................@........=......+.........................*....... +\\......957....659........299..........................%...599..898.+.................464.......606.237..768..416@....=...............228..... +\\.376..$.........*..........*..2.........@557......./.......*.*.....517..........859*.........*....................855...877.427.........*... +\\.........*468..535......500....$................117......726.381........428...$................@........43....472.......*...*...........476. +\\......517................................951........%............-..249..@.....920...........859........*........*....825.393...15.......... +\\...........770.......&16.....278...417......$.....626...-23....954.....#..............................868.......502............*............ +\\.....373..*...................%...*.....254................................................246.#530....................982....179....635.... +\\......*...538.....................362...-...........162.........................180=........*..................278.......*............+..... +\\....138.......922..............................543................6....12....&.............92...150...............*.......994............... +\\................+.....+................388....*..........................*....788............../..................220.............834....... +\\.....................301.593.597.............500..603......928....966................/.............536.......768.............800............ +\\................*64........*.../..&.....924.........*........-...$....................203.............-...+..../...............*..423.&451.. +\\.............453....*......638.....314..*...896....459...............96...................186............581................846....*........ +\\....&188.........624.400...............268....@...........................664...............*...12.943............#733...................... +\\.............................597...765................388......149..468.....+............698......*....143........................426....... +\\.......................878...*.........875..............*..871*.....*..............929....................$.504*..............473.%......... +\\...245..........94.651..*.....915.........*.........40.440........236.................*511.45........994........753..................887.... +\\...#..............*.....459............212...18*964.*.........=71..........768..827............./.....*......................567............ +\\.....787.2..781*....................................827....................*...*..............437.....813.......317.....102.....*333........ +\\..........*.....285............@..-...........304.......821.622.....953...377.997......320....................@./.....%....*..........254... +\\.......877..636.....42......772..419.....189..*................&....*.....................=.17......366*....563......228...153.............. +\\...............*.....$................&....*...839......218.........449......................*..409.....69............................652... +\\.....576......255..............593...397............469..%......#.......+568.......374......499....*...........541..477.........%137..*..... +\\.......*............@319.................$.35..........*.....207...............808*.................933.737...........*.502............367.. +\\.....807....219../.....................436......226@...266........215...................................*................................... +\\..............*...769.....41*....922............................$..*.......271.........350..........677.346......................662....725. +\\..............175............979.*...#........215..............652..39......$....=61......*..154...................................*........ +\\...426..............335*.........487.194.........*42...................790.............+.750.@......&..............253...337....617..717.... +\\...+....908.............489.................../............14...278.../....953.......316.......*856.44.50...../.......*................$.... +\\.........%..90.................437..........848...........................*......714........708..........*223.588.....884....871.801........ +\\494@..........*..33...........*.........779.....424.550....923............779.......*...340........738.......................*....*..131.603 +\\.....50..481.........=.....643...........@......%............*.......815......681..263....*........*...5.....256*11.377$....872.903.*....... +\\.....*...............635.......698..........583...148........708........................323.243..201.....................*..........377.132. +\\...502........883............/..*..............$...*....994.........*....479@.................$......804.443..........584................... +\\.............*..............893..581..534........376..+..........174.119.........138............670...*....$.834............4............... +\\.....+....234...904.323..=..............&.894..........439.@838............*.....*........47........555........*............*........932.... +\\...594............*...$.654.....+.........*........................84.*....7...231.$102.......286.......*760....817.......719.........*..... +\\..................620............806......866.................559......440...........................310...........................590..547. +;
\ No newline at end of file |