Day Twelve

2 files changed, 822 insertions, 0 deletions

diff --git a/2020/input/twelve.txt b/2020/input/twelve.txt
new file mode 100644
index 0000000..16cc747
--- /dev/null
+++ b/2020/input/twelve.txt
@@ -0,0 +1,760 @@
+S3
+R90
+E1
+S3
+E5
+S4
+E5
+N3
+W1
+N3
+F91
+W1
+F49
+W1
+F7
+R90
+F13
+S1
+F87
+L90
+N5
+R90
+E1
+F69
+N4
+F80
+E2
+F15
+N5
+F15
+N4
+E3
+N2
+R90
+E4
+N5
+F71
+W3
+S4
+R270
+F39
+N1
+F100
+R90
+F52
+S2
+W3
+L90
+S1
+F79
+E5
+R90
+F94
+E3
+F87
+N5
+R90
+F50
+W5
+N4
+W4
+S1
+W2
+R180
+W4
+F6
+W2
+N1
+W4
+F89
+L90
+E3
+R90
+F73
+W1
+N4
+F77
+E4
+F42
+N3
+E5
+R180
+F51
+E2
+F22
+N4
+F95
+L90
+E2
+F41
+L90
+F61
+L180
+E1
+R90
+N2
+F32
+E5
+L90
+L180
+E3
+F86
+S3
+L180
+E3
+F76
+W1
+F62
+S2
+F23
+R90
+F60
+E2
+F47
+L90
+S1
+L270
+N3
+N2
+W1
+S4
+S1
+E5
+F43
+S4
+R90
+S5
+N3
+F100
+W5
+R90
+S2
+F30
+E1
+R180
+R90
+F1
+R90
+F32
+N1
+W3
+R180
+F9
+N1
+L90
+E1
+R90
+W5
+L180
+N4
+F57
+F53
+N4
+E5
+R90
+E1
+F32
+R90
+E5
+L180
+E1
+L90
+W4
+S2
+F77
+N2
+R90
+S2
+F68
+S4
+R90
+E3
+F66
+R90
+F85
+S1
+F47
+F25
+R90
+N1
+F65
+R270
+L270
+F90
+S3
+F33
+W5
+N1
+F19
+E1
+L90
+F72
+L90
+F67
+E3
+R90
+E4
+R90
+F6
+S2
+W5
+F43
+W1
+F3
+L270
+N3
+L90
+E5
+N3
+F29
+E4
+R90
+E4
+L90
+F32
+E5
+F52
+N4
+L270
+N1
+W5
+R90
+W5
+N5
+E3
+N5
+W2
+L180
+N2
+E1
+S4
+N1
+W4
+F8
+N2
+W2
+F80
+N3
+F98
+L90
+W3
+L90
+S2
+L90
+F98
+L180
+F12
+E3
+N2
+F60
+N5
+W1
+F54
+W3
+F74
+E4
+S3
+R90
+F94
+L90
+S2
+L90
+N4
+E2
+F83
+R90
+N2
+E1
+F86
+E5
+N1
+R90
+E5
+R180
+F72
+L180
+W5
+L90
+E4
+L90
+E1
+F26
+W4
+F4
+L90
+W4
+L90
+E5
+F92
+R90
+N1
+L90
+N5
+F21
+L90
+L180
+W3
+F76
+L90
+F14
+L90
+E5
+F50
+S5
+F18
+W5
+F27
+S5
+F52
+L180
+N3
+L180
+W2
+N5
+W3
+S2
+F48
+W2
+F57
+R90
+E3
+R180
+E4
+F42
+W2
+F21
+E2
+S4
+E2
+N4
+W4
+S4
+E3
+F23
+S1
+W5
+F70
+S5
+F77
+W5
+S3
+L180
+E4
+L90
+W2
+L90
+E1
+F15
+S4
+F38
+N1
+L90
+F27
+N1
+F34
+L90
+E1
+S2
+E2
+L90
+N3
+F71
+W4
+S4
+F14
+R90
+F58
+R90
+F8
+R90
+E1
+L270
+F12
+E2
+L90
+F9
+R90
+S5
+F48
+S5
+L90
+E1
+F7
+W2
+F97
+S1
+R90
+N5
+E2
+N4
+F20
+R90
+N1
+R90
+F84
+R90
+E3
+S3
+F34
+S3
+F41
+R90
+F15
+L180
+N1
+F4
+L180
+W3
+F50
+S4
+W3
+F45
+W1
+S4
+E2
+L90
+E5
+R270
+S3
+L90
+S4
+F59
+W4
+R180
+F10
+E1
+R90
+S4
+W5
+L90
+F45
+S4
+F92
+R90
+E5
+F36
+S1
+L90
+W1
+S5
+F30
+W5
+F80
+N4
+E2
+R90
+F98
+F7
+S5
+W2
+F1
+N3
+L180
+N2
+F49
+E3
+S5
+S5
+W4
+E5
+E3
+S1
+W1
+F10
+L90
+F40
+E4
+N4
+F25
+R180
+W5
+N5
+W1
+S4
+L90
+F79
+L180
+S1
+F100
+S1
+F34
+S2
+E4
+L90
+N2
+F36
+E1
+N3
+L90
+F42
+R90
+W5
+L270
+F45
+E4
+F95
+N5
+F22
+L90
+F67
+R180
+S5
+E5
+R90
+N1
+R180
+W3
+F80
+E4
+F19
+W5
+N4
+R90
+N5
+F28
+F86
+R180
+R90
+S2
+E1
+N5
+W1
+S3
+W5
+S3
+F51
+W5
+S3
+R90
+R90
+F35
+W2
+F51
+N1
+R180
+S2
+F37
+R270
+W2
+S2
+L90
+L180
+E4
+N1
+L180
+E2
+S1
+F38
+R90
+N2
+W1
+R90
+L180
+E4
+S3
+R180
+E3
+S4
+F65
+E2
+R90
+N1
+E4
+L180
+E5
+R90
+W2
+F22
+W5
+N1
+R90
+E1
+F34
+S1
+R90
+N3
+F62
+F48
+E5
+F85
+E5
+S4
+R90
+E3
+R90
+E1
+F54
+S4
+W3
+W2
+R90
+N5
+W4
+N3
+R180
+E1
+F88
+W5
+F49
+E5
+N4
+W3
+F81
+R90
+F58
+N4
+L90
+F88
+N3
+F87
+E2
+N4
+L90
+N5
+N1
+F87
+E1
+L90
+N3
+W1
+F13
+F3
+N4
+L90
+E3
+S1
+F35
+S4
+F1
+L90
+E1
+N4
+R90
+F60
+N2
+W1
+N1
+R180
+L180
+S3
+R90
+E4
+R180
+W3
+N1
+W1
+F3
+L90
+F8
+W1
+R90
+S1
+F84
+L90
+S3
+F63
+F11
+E1
+F38
+R90
+S3
+R270
+F50
+R90
+F15
+L270
+E1
+S1
+E5
+L180
+N4
+L90
+F37
+N3
+E5
+F13
+L180
+E5
+F88
+E2
+F9
+W3
+F6
+N5
+F75
+N5
+W5
+S5
+E3
+R90
+N5
+E4
+N3
+L180
+F1
+R90
+S3
+E1
+S4
+E5
+N3
+R270
+E3
+L90
+N3
+S2
+L90
+S5
+F90
+R90
+N1
+R90
+F50
+F33
+W3
+F23
+E3
+R90
+F81
+E1
+N3
+R180
+F16
+S2
+F35
+R90
+W5
+F31
+R90
+S2
+L180
+E5
+R180
+F89
+N1
+L90
+F68
+W3
+R90
+W3
+N1
+L90
+N4
+L180
+S5
+R180
+N4
+R90
+W5
+N5
+L180
+N2
+E4
+N1
+W4
+F98
+S5
+F70
+W5
+F76
diff --git a/2020/twelve.nim b/2020/twelve.nim
new file mode 100644
index 0000000..fc93243
--- /dev/null
+++ b/2020/twelve.nim
@@ -0,0 +1,62 @@
+# Day Twelve: Rain Risk
+import os, strutils, sequtils, math, sugar
+
+let input: string = paramStr(1)
+let instructions: seq[tuple[action: char, value: int]] =
+  map(split(strip(readFile(input)), '\n'),
+    instruction => (instruction[0], parseInt(instruction[1..^1])))
+
+var ferry, actual: tuple[latitude, longitude, bearing: int] = (0, 0, 0)
+var waypoint: tuple[latitude, longitude: int] = (1, 10)
+for instruction in instructions:
+  let value: int = instruction.value
+  let current: tuple[latitude, longitude: int] = waypoint
+  case instruction.action
+  of 'N':
+    inc(ferry.latitude, value)
+    inc(waypoint.latitude, value)
+  of 'S':
+    dec(ferry.latitude, value)
+    dec(waypoint.latitude, value)
+  of 'E':
+    inc(ferry.longitude, value)
+    inc(waypoint.longitude, value)
+  of 'W':
+    dec(ferry.longitude, value)
+    dec(waypoint.longitude, value)
+  of 'L':
+    inc(ferry.bearing, value)
+    let bearing: float = degToRad(toFloat(value))
+    case value
+    of 0, 180:
+      waypoint.latitude = sgn(cos(bearing)) * current.latitude
+      waypoint.longitude = sgn(cos(bearing)) * current.longitude
+    of 90, 270:
+      waypoint.latitude = sgn(sin(bearing)) * current.longitude
+      waypoint.longitude = -sgn(sin(bearing)) * current.latitude
+    else:
+      discard
+  of 'R':
+    dec(ferry.bearing, value)
+    let bearing: float = degToRad(toFloat(value))
+    case value
+    of 0, 180:
+      waypoint.latitude = sgn(cos(bearing)) * current.latitude
+      waypoint.longitude = sgn(cos(bearing)) * current.longitude
+    of 90, 270:
+      waypoint.latitude = -sgn(sin(bearing)) * current.longitude
+      waypoint.longitude = sgn(sin(bearing)) * current.latitude
+    else:
+      discard
+  of 'F':
+    let bearing: float = degToRad(toFloat(ferry.bearing))
+    if abs(cos(bearing)) == 1.0:
+      inc(ferry.longitude, sgn(cos(bearing)) * value)
+    elif abs(sin(bearing)) == 1.0:
+      inc(ferry.latitude, sgn(sin(bearing)) * value)
+    inc(actual.longitude, value * waypoint.longitude)
+    inc(actual.latitude, value * waypoint.latitude)
+  else:
+    discard
+echo abs(ferry.longitude) + abs(ferry.latitude)
+echo abs(actual.longitude) + abs(actual.latitude)