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Yudong Jin
7257641e0e
* Retranslate the complete Japanese online edition from Chinese * Fit Japanese homepage labels and localize heading permalinks * Point Japanese contribution instructions to the Japanese preview * Replace locale conditionals with multilingual UI tables
38 lines
1.0 KiB
Ruby
38 lines
1.0 KiB
Ruby
=begin
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File: climbing_stairs_backtrack.rb
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Created Time: 2024-05-29
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Author: Xuan Khoa Tu Nguyen ([email protected])
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=end
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### バックトラッキング ###
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def backtrack(choices, state, n, res)
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# n 段目に到達したら、方法の数を 1 増やす
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res[0] += 1 if state == n
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# すべての選択肢を走査する
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for choice in choices
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# 枝刈り：n 段目を越えてはならない
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next if state + choice > n
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# 試行：選択を行い、状態を更新する
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backtrack(choices, state + choice, n, res)
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end
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# 復元
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end
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### 階段の上り方：バックトラッキング ###
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def climbing_stairs_backtrack(n)
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choices = [1, 2] # 1 段または 2 段上ることを選択できる
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state = 0 # 0 段目から上り始める
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res = [0] # res[0] に方法の数を記録する
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backtrack(choices, state, n, res)
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res.first
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end
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### 実行用コード ###
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if __FILE__ == $0
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n = 9
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res = climbing_stairs_backtrack(n)
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puts "#{n} 段の階段を上る方法は全部で #{res} 通り"
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end
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