55 lines
983 B
Crystal
55 lines
983 B
Crystal
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require "advent"
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INPUT = input(2020, 18).lines
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class Array(T)
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def push_op(op)
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r = pop
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l = pop
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self << ((op == '*') ? (l*r) : (l+r))
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end
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def has_op?
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!empty? && last != '('
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end
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end
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def translate(toks, prec)
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output = [] of Int64
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stack = [] of Char
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toks.each do |tok|
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case tok
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when .number? then output << tok.to_i64
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when '(' then stack << '('
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when ')'
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while stack.has_op?
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output.push_op(stack.pop)
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end
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stack.pop
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else
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while stack.has_op? && prec[stack.last] < prec[tok]
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output.push_op(stack.pop)
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end
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stack << tok
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end
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end
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while stack.has_op?
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output.push_op(stack.pop)
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end
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output.last
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end
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def part1(input)
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input.sum do |line|
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translate(line.chars.reject &.==(' '), {'*' => 0, '+' => 0})
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end
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end
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def part2(input)
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input.sum do |line|
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translate(line.chars.reject &.==(' '), {'*' => 1, '+' => 0})
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end
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end
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puts part1(INPUT.clone)
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puts part2(INPUT.clone)
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