40 lines
1,014 B
Text
40 lines
1,014 B
Text
func gen_expr() is cached {
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var x = ['-', '']
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var y = ['+', '-', '']
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gather {
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cartesian([x,y,y,y,y,y,y,y,y], {|a,b,c,d,e,f,g,h,i|
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take("#{a}1#{b}2#{c}3#{d}4#{e}5#{f}6#{g}7#{h}8#{i}9")
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})
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}
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}
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func eval_expr(expr) is cached {
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expr.scan(/([-+]?\d+)/).sum_by { Num(_) }
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}
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func sum_to(val) {
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gen_expr().grep { eval_expr(_) == val }
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}
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func max_solve() {
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gen_expr().grep { eval_expr(_) >= 0 } \
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.group_by { eval_expr(_) } \
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.max_by {|_,v| v.len }
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}
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func min_solve() {
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var h = gen_expr().group_by { eval_expr(_) }
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for i in (0..Inf) { h.exists(i) || return i }
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}
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func highest_sums(n=10) {
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gen_expr().map { eval_expr(_) }.uniq.sort.reverse.first(n)
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}
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sum_to(100).each { say "100 = #{_}" }
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var (n, solutions) = max_solve()...
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say "Sum of #{n} has the maximum number of solutions: #{solutions.len}"
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say "Lowest positive sum that can't be expressed : #{min_solve()}"
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say "Highest sums: #{highest_sums()}"
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