Clean up some solutions.

day6.cr

@@ -2,20 +2,12 @@ require "advent"
 INPUT = input(2020, 6).split("\n\n")
 
 def part1
-  input = INPUT.clone
-  answers = input.map do |i|
-    i.chars.uniq!.count &.ascii_letter?
-  end
-  puts answers.sum
+  INPUT.sum &.chars.uniq!.count(&.ascii_letter?)
 end
 
 def part2
-  input = INPUT.clone
-  sol = input.map do |i|
-    i.split("\n").reject(&.empty?).map(&.chars.to_set).reduce { |s1, s2| s1 & s2 }
-  end
-  puts(sol.map(&.size).sum)
+  INPUT.sum &.lines.map(&.chars.to_set).intersect.size
 end
 
-part1
-part2
+puts part1
+puts part2

day7.cr

@@ -2,18 +2,19 @@ require "advent"
 
 INPUT = input(2020, 7).lines.map(&.chomp).map do |s|
   data = s.match(/^([a-z ]+) bags contain (.*).$/).not_nil!
-  {data[1], data[2].split(", ").map(&.rchop(" bags").rchop(" bag")) }
+  contents = data[2].split(", ").compact_map do |s|
+    s.match(/(\d+) (.*) bags?/).try { |m| {m[1].to_i32, m[2]} }
+  end
+  {data[1], contents}
 end
 
 def build_graph(input)
   gr = Graph(String).new
   seen = Set(String).new
   input.each do |i|
-    next if i[1] == ["no other"]
     seen << i[0]
     i[1].each do |to|
-      n, _, m = to.partition(" ")
-      n = n.to_i32
+      n, m = to
       gr.add_edge(i[0], m, n)
     end
   end

day8.cr

@@ -1,31 +1,7 @@
 require "advent"
-INPUT = input(2020, 8).lines
-
-def part1
-  acc = 0
-  pc = 0
-  visited = Set(Int32).new
-  input = INPUT.clone.map do |s|
-    code, int = s.split(" ")
-    {code, int.to_i32}
-  end
-
-  loop do
-    if visited.includes? pc
-      break
-    end
-    visited << pc
-    code, int = input[pc]
-    case input[pc][0]
-    when "acc"
-      acc += int
-      pc += 1
-    when "jmp"
-      pc += int
-    when "nop"
-      pc += 1
-    end
-  end
+INPUT = input(2020, 8).lines.map do |s|
+  code, int = s.split(" ")
+  {code, int.to_i32}
 end
 
 def run(prog)
@@ -33,50 +9,34 @@ def run(prog)
   pc = 0
   visited = Set(Int32).new
   loop do
-    if visited.includes? pc
-      return false
-    end
-    return acc if pc >= prog.size
+    return {:term, acc} if pc >= prog.size
+    return {:inf, acc} if visited.includes? pc
+      
     visited << pc
     code, int = prog[pc]
-    case prog[pc][0]
+    case code
     when "acc"
       acc += int
-      pc += 1
     when "jmp"
-      pc += int
-    when "nop"
-      pc += 1
+      pc += int - 1
     end
+    pc += 1
   end
 end
 
+def part1
+  run(INPUT)[1]
+end
+
 def part2
-  input = INPUT.clone.map do |s|
-    code, int = s.split(" ")
-    {code, int.to_i32}
-  end
-
-  jnp = [] of Int32
-  input.each_with_index do |e, i|
-    op, int = e
-    jnp << i if op == "jmp" || op == "nop"
-  end
-
+  jnp = INPUT.find_indices { |e| e[0] == "jmp" || e[0] == "nop" }
   jnp.each do |i|
-    prog = input.clone
-    if prog[i][0] == "jmp"
-      prog[i] = {"nop", prog[i][1]}
-    else
-      prog[i] = {"jmp", prog[i][1]}
-    end
+    prog = INPUT.clone
+    op, int = prog[i]
+    prog[i] = {op.tr("jmpnop", "nopjmp"), int}
 
-    case i = run(prog)
-    when Bool
-      next
-    when Int32
-      return i
-    end
+    code, acc = run(prog)
+    return acc if code == :term
   end
 end