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=begin
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File: max_product_cutting.rb
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Created Time: 2024-05-07
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Author: Xuan Khoa Tu Nguyen (ngxktuzkai2000@gmail.com)
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=end
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### 最大切分乘积：贪心 ###
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def max_product_cutting(n)
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# 当 n <= 3 时，必须切分出一个 1
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return 1 * (n - 1) if n <= 3
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# 贪心地切分出 3 ，a 为 3 的个数，b 为余数
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a, b = n / 3, n % 3
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# 当余数为 1 时，将一对 1 * 3 转化为 2 * 2
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return (3.pow(a - 1) * 2 * 2).to_i if b == 1
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# 当余数为 2 时，不做处理
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return (3.pow(a) * 2).to_i if b == 2
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# 当余数为 0 时，不做处理
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3.pow(a).to_i
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end
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### Driver Code ###
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if __FILE__ == $0
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n = 58
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# 贪心算法
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res = max_product_cutting(n)
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puts "最大切分乘积为 #{res}"
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end
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