diff --git a/2019/day03/input b/2019/day03/input new file mode 100644 index 0000000..e023935 --- /dev/null +++ b/2019/day03/input @@ -0,0 +1,2 @@ +R990,U408,L583,U275,R483,U684,R437,U828,R108,U709,R378,U97,R252,D248,R413,U750,R428,D545,R570,D795,L204,D975,L557,U160,L861,U106,R436,U934,R81,D237,R660,U704,L451,U135,R282,D391,R39,D109,R125,U918,R214,U481,R853,U825,L91,D763,R335,U868,R42,U218,R152,D429,R414,D607,R28,U436,R7,U770,L215,D373,R209,U440,L536,U120,R900,D46,R635,D75,R58,U267,L581,U474,L858,U172,R725,U54,R291,D274,L583,D743,L130,U563,R137,U524,R659,D997,R131,D364,R883,D222,R628,U579,R801,D890,L519,D749,L620,U60,L759,D759,R376,U769,L910,D570,L814,U954,L153,D42,L784,D66,L844,U29,L794,D342,L924,U825,R447,U828,R404,D52,L330,D876,R125,U203,R245,U936,R866,D804,L186,U693,L620,D722,L32,D735,L191,D217,R68,U209,L736,U365,R280,U608,L450,D240,L282,U434,R589,U94,R470,D5,R49,U407,R552,D651,L69,U518,L358,D130,L710,D929,L315,U345,L511,D229,L557,U44,L890,D702,L181,D61,L208,U553,R878,U354,R787,U624,L961,D92,L891,U70,R203,U255,R532,U154,R299,U934,L609,D985,R115,U757,L13,D368,R936,D742,L412,U346,R56,D67,R371,D175,R868,U107,R806,D530,L40,U153,R374,D223,R517,D481,L194,U545,L356,U906,L999,D885,R967,U407,L141,U927,L489,U959,L992,U638,R332,U51,R256,U901,L891,U803,L885,U804,L242,U180,R277,U693,R935,D253,L68,D153,L614,D596,L999,D633,R995,D803,R17,U303,L569,U231,R737,D970,L45,D860,L225,D65,R41,D313,R698,D340,R599,D531,R55,D568,L911,D547,R196,D228,R868,D227,R262,U525,R104,D625,R570,U968,L276,D586,R690,D73,L336,U287,R294,U148,R781,D395,R478,D804,L429,U872,L351,D910,L597,U726,L320,D964,R928,U2,R540,D325,L222 +L998,U662,R342,U104,R140,U92,R67,D102,L225,U265,R641,U592,L295,D77,R415,U908,L640,D381,R312,U44,R424,D847,R892,D625,L337,D344,L917,D914,R127,D273,L627,U812,L200,D262,R226,U273,R911,U597,L888,U28,R921,U464,R254,U771,R818,D808,L239,D225,L280,U785,R322,D831,L622,U506,R139,U12,L491,D572,L172,U685,R54,U747,L812,D717,R874,U428,L867,U174,R360,D36,R217,D539,R210,D791,L82,D665,L190,D313,R649,U849,R63,U385,R105,U806,L207,U697,L823,D272,R830,D952,L386,U987,R775,U517,R139,D756,R545,D973,L743,D286,R261,U448,R946,U884,L903,D142,R28,D374,R259,U403,R689,D245,L302,D134,R710,U762,L67,D561,R801,D140,L887,U346,L227,U682,L350,D218,L711,U755,R226,D277,R114,D61,R992,U602,L191,U640,R733,D329,R862,U242,R754,D161,L52,D974,L251,D444,L552,U977,R174,U483,R869,D955,R925,U693,R610,D353,L843,U148,L866,D167,R412,D31,L847,D979,L282,D797,L837,U473,L402,U193,L332,D603,R48,D589,L760,D673,L843,U428,R779,D592,L688,D141,R851,D642,R559,U939,R999,D64,L297,U817,R670,U322,L768,D936,L39,U95,L342,U849,L692,U714,L732,D734,L373,U66,L577,D453,R336,U760,L217,U542,R920,U24,R529,D594,L34,D79,R877,D965,R932,U460,R879,U26,R803,U876,L780,U956,L235,D270,L315,D577,R835,U750,R414,D584,L828,U335,L563,U238,L815,U780,L550,U18,R743,D54,L816,U344,L806,D197,L518,D682,L835,U255,L666,U442,L286,D543,R102,D52,L570,D787,L763,D223,R279,D892,L828,D111,L554,D452,R575,D299,R932,D187,L439,U616,L278,D701,L360,D524,L891,U953,L896,U788,R776,U782,L71,D741,L652,U121,R669,D809,L662,U319,R392,D313,R870,U794,R937,D469,R571,D761,R947 diff --git a/2019/day03/main.go b/2019/day03/main.go new file mode 100644 index 0000000..4ac5fbc --- /dev/null +++ b/2019/day03/main.go @@ -0,0 +1,125 @@ +package main + +import ( + "bufio" + "fmt" + "log" + "math" + "os" + "strconv" + "strings" +) + +const MaxInt = int(^uint(0) >> 1) + +func main() { + inp := StdinToStringSlice() + part1(inp) +} + +func part1(inp []string) { + var allWires []*Wire + for _, v := range inp { + wire := NewWire() + wrk := strings.Split(v, ",") + for _, p := range wrk { + wire.Go(p) + } + allWires = append(allWires, wire) + } + var shortestCoord, fewestStepsCoord Coord + shortest := MaxInt + shortestSteps := MaxInt + for p1i, p1 := range allWires[0].path { + if p1.x == 0 && p1.y == 0 { + continue + } + for p2i, p2 := range allWires[1].path { + if p2.x == 0 && p2.y == 0 { + continue + } + if p1.equals(p2) { + wrk := manhattanDistance(p1.x, p1.y, 0, 0) + if wrk < shortest { + shortest = wrk + shortestCoord = p1 + } + if p1i+p2i < shortestSteps { + shortestSteps = p1i + p2i + fewestStepsCoord = p1 + } + } + } + } + fmt.Println("Closest:", shortest, shortestCoord) + fmt.Println("Fewest Steps:", shortestSteps, fewestStepsCoord) +} + +type Wire struct { + curr Coord + path []Coord +} + +func NewWire() *Wire { + w := Wire{} + w.curr = Coord{0, 0} + w.path = append(w.path, w.curr) + return &w +} + +func (w *Wire) Go(cmd string) { + dir := cmd[0] + length := Atoi(cmd[1:]) + for length > 0 { + w.Move(dir) + w.path = append(w.path, w.curr) + length-- + } +} + +func (w *Wire) Move(dir byte) { + switch dir { + case 'U': + w.curr = Coord{w.curr.x, w.curr.y - 1} + case 'R': + w.curr = Coord{w.curr.x + 1, w.curr.y} + case 'D': + w.curr = Coord{w.curr.x, w.curr.y + 1} + case 'L': + w.curr = Coord{w.curr.x - 1, w.curr.y} + } +} + +type Coord struct { + x, y int +} + +func (c Coord) equals(b Coord) bool { + return c.x == b.x && c.y == b.y +} + +func (c Coord) string() string { + return fmt.Sprintf("{%2d,%2d}", c.x, c.y) +} + +func manhattanDistance(x1, y1, x2, y2 int) int { + return int(math.Abs(float64(x1)-float64(x2)) + math.Abs(float64(y1)-float64(y2))) +} + +func StdinToStringSlice() []string { + var input []string + scanner := bufio.NewScanner(os.Stdin) + for scanner.Scan() { + input = append(input, scanner.Text()) + } + return input +} + +func Atoi(i string) int { + var ret int + var err error + if ret, err = strconv.Atoi(i); err != nil { + log.Fatal("Invalid Atoi") + } + return ret +} diff --git a/2019/day03/problem b/2019/day03/problem new file mode 100644 index 0000000..57bdbc1 --- /dev/null +++ b/2019/day03/problem @@ -0,0 +1,114 @@ +Advent of Code + +--- Day 3: Crossed Wires --- + + The gravity assist was successful, and you're well on your way to the Venus refuelling station. During the rush back on Earth, the fuel management + system wasn't completely installed, so that's next on the priority list. + + Opening the front panel reveals a jumble of wires. Specifically, two wires are connected to a central port and extend outward on a grid. You trace the + path each wire takes as it leaves the central port, one wire per line of text (your puzzle input). + + The wires twist and turn, but the two wires occasionally cross paths. To fix the circuit, you need to find the intersection point closest to the central + port. Because the wires are on a grid, use the Manhattan distance for this measurement. While the wires do technically cross right at the central port + where they both start, this point does not count, nor does a wire count as crossing with itself. + + For example, if the first wire's path is R8,U5,L5,D3, then starting from the central port (o), it goes right 8, up 5, left 5, and finally down 3: + + ........... + ........... + ........... + ....+----+. + ....|....|. + ....|....|. + ....|....|. + .........|. + .o-------+. + ........... + + Then, if the second wire's path is U7,R6,D4,L4, it goes up 7, right 6, down 4, and left 4: + + ........... + .+-----+... + .|.....|... + .|..+--X-+. + .|..|..|.|. + .|.-X--+.|. + .|..|....|. + .|.......|. + .o-------+. + ........... + + These wires cross at two locations (marked X), but the lower-left one is closer to the central port: its distance is 3 + 3 = 6. + + Here are a few more examples: + + • R75,D30,R83,U83,L12,D49,R71,U7,L72 + U62,R66,U55,R34,D71,R55,D58,R83 = distance 159 + • R98,U47,R26,D63,R33,U87,L62,D20,R33,U53,R51 + U98,R91,D20,R16,D67,R40,U7,R15,U6,R7 = distance 135 + + What is the Manhattan distance from the central port to the closest intersection? + +--- Part Two --- + + It turns out that this circuit is very timing-sensitive; you actually need to minimize the signal delay. + + To do this, calculate the number of steps each wire takes to reach each intersection; choose the intersection where the sum of both wires' steps is + lowest. If a wire visits a position on the grid multiple times, use the steps value from the first time it visits that position when calculating the + total value of a specific intersection. + + The number of steps a wire takes is the total number of grid squares the wire has entered to get to that location, including the intersection being + considered. Again consider the example from above: + + ........... + .+-----+... + .|.....|... + .|..+--X-+. + .|..|..|.|. + .|.-X--+.|. + .|..|....|. + .|.......|. + .o-------+. + ........... + + In the above example, the intersection closest to the central port is reached after 8+5+5+2 = 20 steps by the first wire and 7+6+4+3 = 20 steps by the + second wire for a total of 20+20 = 40 steps. + + However, the top-right intersection is better: the first wire takes only 8+5+2 = 15 and the second wire takes only 7+6+2 = 15, a total of 15+15 = 30 + steps. + + Here are the best steps for the extra examples from above: + + • R75,D30,R83,U83,L12,D49,R71,U7,L72 + U62,R66,U55,R34,D71,R55,D58,R83 = 610 steps + • R98,U47,R26,D63,R33,U87,L62,D20,R33,U53,R51 + U98,R91,D20,R16,D67,R40,U7,R15,U6,R7 = 410 steps + + What is the fewest combined steps the wires must take to reach an intersection? + + Both parts of this puzzle are complete! They provide two gold stars: ** + + At this point, you should return to your Advent calendar and try another puzzle. + + If you still want to see it, you can get your puzzle input. + +References + + Visible links + . https://adventofcode.com/ + . https://adventofcode.com/2019/about + . https://adventofcode.com/2019/events + . https://adventofcode.com/2019/settings + . https://adventofcode.com/2019/auth/logout + . Advent of Code Supporter + https://adventofcode.com/2019/support + . https://adventofcode.com/2019 + . https://adventofcode.com/2019 + . https://adventofcode.com/2019/support + . https://adventofcode.com/2019/sponsors + . https://adventofcode.com/2019/leaderboard + . https://adventofcode.com/2019/stats + . https://adventofcode.com/2019/sponsors + . https://en.wikipedia.org/wiki/Taxicab_geometry + . https://adventofcode.com/2019 + . https://adventofcode.com/2019/day/3/input diff --git a/2019/day03/testinput1 b/2019/day03/testinput1 new file mode 100644 index 0000000..620a05e --- /dev/null +++ b/2019/day03/testinput1 @@ -0,0 +1,2 @@ +R75,D30,R83,U83,L12,D49,R71,U7,L72 +U62,R66,U55,R34,D71,R55,D58,R83 diff --git a/2019/day03/testinput2 b/2019/day03/testinput2 new file mode 100644 index 0000000..4f3a2a4 --- /dev/null +++ b/2019/day03/testinput2 @@ -0,0 +1,2 @@ +R98,U47,R26,D63,R33,U87,L62,D20,R33,U53,R51 +U98,R91,D20,R16,D67,R40,U7,R15,U6,R7