使用Ruby使哈希值相互查找

Question

我在此數組中有幾個time_tables 。 有四個time_tables通過它們的start_location - end_location和start_date - end_date相互線性關聯。

當第一個time_table結束時，另一個time_table開始，依此類推。

我的代碼：

arr =   [
      { name: 01, start_date: '2014-04-24 22:03:00', start_location: 'A', end_date: '2014-04-24 22:10:00', end_location: 'B' },
      { name: 05, start_date: '2014-04-24 22:10:00', start_location: 'C', end_date: '2014-04-24 23:10:00', end_location: 'D' },
      { name: 01, start_date: '2014-04-24 17:10:00', start_location: 'X', end_date: '2014-04-24 20:10:00', end_location: 'B' },
      { name: 01, start_date: '2014-04-24 17:10:00', start_location: 'Z', end_date: '2014-04-24 20:10:00', end_location: 'B' },
      { name: 06, start_date: '2014-04-24 20:15:00', start_location: 'B', end_date: '2014-04-24 22:10:00', end_location: 'C' },
      { name: 03, start_date: '2014-04-24 23:15:00', start_location: 'D', end_date: '2014-04-24 00:10:00', end_location: 'E' }
    ]
new_array = []

i = 0
while i <= 5 do
  if arr[i][:end_location] == arr[i+1][:start_location] && arr[i][:start_date] <= arr[i+1][:start_date]
    new_array << arr[i+1]
  end
  i = i + 1
end

這是我想要的結果：

  # My expexpected result will be this:
  #     [
  #     { name: 01, start_date: '2014-04-24 22:03:00', start_location: 'A', end_date: '2014-04-24 22:10:00', end_location: 'B' },
  #    { name: 06, start_date: '2014-04-24 22:15:00', start_location: 'B', end_date: '2014-04-24 22:20:00', end_location: 'C' },
  #    { name: 05, start_date: '2014-04-24 22:20:00', start_location: 'C', end_date: '2014-04-24 23:10:00', end_location: 'D' },
  #    { name: 03, start_date: '2014-04-24 23:15:00', start_location: 'D', end_date: '2014-04-24 00:10:00', end_location: 'E' }
  # 

  ]

但是我的算法似乎不好。 感謝您為這項工作提供的見識。

Answer 1

這將通過連續的結束和開始位置“加入”您的時間序列。

 def span x; x[:end_location].ord - x[:start_location].ord; end
 def diff x, y; x[:start_location].ord - y[:start_location].ord; end
 arr = arr.sort_by { |x| [x[:start_location], span(x)] }
 prev = arr[0]
 arr = arr.slice_before { |e|
   prev, prev2 = e, prev
   diff(prev, prev2) != 0
 }.to_a.map(&:first).chunk(&method(:span)).first[1]

例如，我得到

 arr.map { |x| [x[:start_location], x[:end_location] }
 => [["A", "B"], ["B", "C"], ["C", "D"], ["D", "E"]]

Answer 2

您不是真的在尋找最長的線性后續時間表嗎？ 我想通過評論來澄清這一點，但我無權發表評論。 在輸入和輸出中B的start_date（和start_location B）的值之間也存在差異，所以我假設這是一個錯誤。

考慮到您想要找到最長的線性后續時間表，我已經編寫了解決方案。

require 'date'

def getLLTT(time_tables)

    longest = []
    time_tables.sort_by! do |time_table|
        DateTime.parse(time_table[:start_date]).to_time
    end

    0.upto(time_tables.size-1) do |i|

        long_for_i = [time_tables[i]]
        0.upto(i-1) do |j|
            j_end_date = DateTime.parse(longest[j][-1][:end_date]).to_time
            i_start_date = DateTime.parse(time_tables[i][:start_date]).to_time
            if j_end_date <= i_start_date 
                if longest[j][-1][:end_location].eql? time_tables[i][:start_location]
                    if longest[j].size + 1 > long_for_i.size
                        long_for_i = longest[j] + [time_tables[i]]
                    end
                end
            end
        end

        longest[i] = long_for_i
    end
    return longest[-1]
end

puts getLLTT(arr)

所以給定輸入：

arr =   [
{ name: 01, start_date: '2014-04-24 22:03:00', start_location: 'A', end_date: '2014-04-24 22:10:00', end_location: 'B' },
  { name: 05, start_date: '2014-04-24 22:10:00', start_location: 'C', end_date: '2014-04-24 23:10:00', end_location: 'D' },
  { name: 01, start_date: '2014-04-24 17:10:00', start_location: 'X', end_date: '2014-04-24 20:10:00', end_location: 'B' },
  { name: 01, start_date: '2014-04-24 17:10:00', start_location: 'Z', end_date: '2014-04-24 20:10:00', end_location: 'B' },
  { name: 06, start_date: '2014-04-24 20:15:00', start_location: 'B', end_date: '2014-04-24 22:10:00', end_location: 'C' },
  { name: 03, start_date: '2014-04-24 23:15:00', start_location: 'D', end_date: '2014-04-24 00:10:00', end_location: 'E' }
]

輸出將是：

[
{:name=>1, :start_date=>"2014-04-24 17:10:00", :start_location=>"Z", :end_date=>"2014-04-24 20:10:00", :end_location=>"B"}
{:name=>6, :start_date=>"2014-04-24 20:15:00", :start_location=>"B", :end_date=>"2014-04-24 22:10:00", :end_location=>"C"}
{:name=>5, :start_date=>"2014-04-24 22:10:00", :start_location=>"C", :end_date=>"2014-04-24 23:10:00", :end_location=>"D"}
{:name=>3, :start_date=>"2014-04-24 23:15:00", :start_location=>"D", :end_date=>"2014-04-24 00:10:00", :end_location=>"E"}
]