Year 2024 Day 7

2024/day07.rb

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+lines = STDIN.read.split("\n")
+
+ADD = '+'
+MUL = '*'
+CON = '||'
+P1_OPTS = [ADD, MUL]
+P2_OPTS = [ADD, MUL, CON]
+
+def total_calibration(equations, possible_operators)
+  result = 0
+  equations.each do |(test_value, operands)|
+    choices = possible_operators.repeated_permutation(operands.size - 1)
+    choices.each do |operators|
+      res = operators.zip(operands[1..]).reduce(operands.first) do |acc, (opt, opd)|
+        case opt
+        when ADD
+          acc += opd
+        when MUL
+          acc *= opd
+        else
+          acc = (acc.to_s + opd.to_s).to_i
+        end
+      end
+
+      if res == test_value
+        result += res
+        break
+      end
+    end
+  end
+  result
+end
+
+equations = lines.map do |line|
+  l, r = line.split(':')
+  [l.to_i, r.split.map(&:to_i)]
+end
+
+puts total_calibration(equations, P1_OPTS)
+puts total_calibration(equations, P2_OPTS)

2024/examples/day07.txt

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+190: 10 19
+3267: 81 40 27
+83: 17 5
+156: 15 6
+7290: 6 8 6 15
+161011: 16 10 13
+192: 17 8 14
+21037: 9 7 18 13
+292: 11 6 16 20