Created
April 2, 2014 09:28
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| City = Struct.new(:name, :neighbours, :way) | |
| def solution(k, t) | |
| n = t.size-1 | |
| q = [] | |
| path = [k] | |
| for i in (0..n) do | |
| q << City.new(i, [], []) | |
| end | |
| for i in (0..n) do | |
| if i != t[i] #&& i != k | |
| q[i].neighbours << t[i] | |
| q[t[i]].neighbours << i | |
| end | |
| end | |
| corner_q = q.select { |i| i.neighbours.size == 1 } | |
| stack = [k] | |
| visited = [] | |
| visited[k] = 1 | |
| while !stack.empty? do | |
| v = stack.pop | |
| q[v].neighbours.each do |i| | |
| if visited[i] != 1 | |
| visited[i] = 1 | |
| if v != k | |
| q[i].way = q[v].way + [v] | |
| end | |
| stack << i | |
| end | |
| end | |
| end | |
| set = [] | |
| corner_q. | |
| sort! do |a, b| | |
| if a.way.size == b.way.size | |
| b.name <=> a.name | |
| else | |
| a.way.size <=> b.way.size | |
| end | |
| end. | |
| reverse. | |
| each do |city| | |
| city.way -= set | |
| set += city.way | |
| end | |
| corner_q. | |
| sort! do |a, b| | |
| if a.way.size == b.way.size | |
| b.name <=> a.name | |
| else | |
| a.way.size <=> b.way.size | |
| end | |
| end | |
| path += corner_q.map(&:name).reverse | |
| path.uniq | |
| end |
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