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This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode charactersOriginal file line number Diff line number Diff line change @@ -36,7 +36,7 @@ def move(depth=1, c=@coins, m=[]) end end end (@maxlen-3).downto(4) do |i| if c[i] != ' ' and c[i+1] != ' ' (i-2).downto(0) do |j| if valid? c, i, j -
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This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode charactersOriginal file line number Diff line number Diff line change @@ -0,0 +1,98 @@ #!/usr/bin/ruby class Coins def initialize(maxcoins, maxdepth=maxcoins, maxlen=maxcoins+2) @maxcoins = maxcoins @maxdepth = maxdepth @maxlen = maxlen @solution = nil @coins = Array.new(@maxlen, ' ') 0.upto(@maxcoins-1) do |c| @coins[c] = c%2 == 0 ? 'o' : 'O' end @final="#{'O'*(@maxcoins/2)}#{'o'*(@maxcoins/2)}" if @maxcoins % 2 == 1 @final += 'o' end end def move(depth=1, c=@coins, m=[]) return false if depth > @maxdepth+1 if final? c @solution = m return true end 0.upto(@maxlen-4) do |i| if c[i] != ' ' and c[i+1] != ' ' # a coin pair (i+2).upto(@maxlen-2) do |j| if valid? c, i, j return false if not m.empty? and [j, i] == m[-1] if move depth+1, swapcoins(c, i, j), m m.push [i, j] return true end end end end end (@maxlen-3).downto(2) do |i| if c[i] != ' ' and c[i+1] != ' ' (i-2).downto(0) do |j| if valid? c, i, j return false if not m.empty? and [j, i] == m[-1] if move depth+1, swapcoins(c, i, j), m m.push [i, j] return true end end end end end false end def play puts "Solution with #{@solution.length} moves:" @coins = Array.new(@maxlen, ' ') 0.upto(@maxcoins-1) do |c| @coins[c] = c%2 == 0 ? 'o' : 'O' end @solution.reverse.each do |mv| @coins=swapcoins @coins, mv[0], mv[1], true end end private def swapcoins(coins, start_coin, end_coin, print=false) c = Array.new(coins) c[start_coin], c[end_coin] = c[end_coin], c[start_coin] c[start_coin+1], c[end_coin+1] = c[end_coin+1], c[start_coin+1] puts "Swapping #{cstring coins} <-> #{cstring c}" if print c end def final?(coins) coins.join.strip.eql? @final or coins.join.strip.eql? @final.reverse end def valid?(coins, start_coin, end_coin) return false if coins[end_coin] != ' ' or coins[end_coin + 1] != ' ' # space return false if coins[end_coin - 1] == ' ' and coins[end_coin + 2] == ' ' # outside return false if (end_coin - start_coin).abs <= 2 # translation true end def cstring(coins) coins.join.gsub(' ', '_') end end number = ARGV[0].to_i coins = Coins.new(number) if coins.move coins.play else puts "No solution" end