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32 lines
777 B
32 lines
777 B
=begin
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File: climbing_stairs_constraint_dp.rb
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Created Time: 2024-05-29
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Author: Xuan Khoa Tu Nguyen (ngxktuzkai2000@gmail.com)
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=end
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### 带约束爬楼梯：动态规划 ###
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def climbing_stairs_constraint_dp(n)
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return 1 if n == 1 || n == 2
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# 初始化 dp 表，用于存储子问题的解
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dp = Array.new(n + 1) { Array.new(3, 0) }
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# 初始状态：预设最小子问题的解
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dp[1][1], dp[1][2] = 1, 0
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dp[2][1], dp[2][2] = 0, 1
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# 状态转移：从较小子问题逐步求解较大子问题
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for i in 3...(n + 1)
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dp[i][1] = dp[i - 1][2]
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dp[i][2] = dp[i - 2][1] + dp[i - 2][2]
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end
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dp[n][1] + dp[n][2]
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end
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### Driver Code ###
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if __FILE__ == $0
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n = 9
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res = climbing_stairs_constraint_dp(n)
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puts "爬 #{n} 阶楼梯共有 #{res} 种方案"
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end
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