mirror of
https://github.com/TheAlgorithms/Ruby
synced 2024-12-26 21:58:56 +01:00
45 lines
747 B
Ruby
45 lines
747 B
Ruby
# Given an integer row_index, return the rowIndexth (0-indexed) row of the Pascal's triangle.
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# Example 1:
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#
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# Input: row_index = 3
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# Output: [1,3,3,1]
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#
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# Example 2:
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#
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# Input: row_index = 0
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# Output: [1]
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#
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# Example 3:
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#
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# Input: row_index = 1
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# Output: [1,1]
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# Complexity Analysis
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#
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# Time complexity: O(k).
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# Space complexity: O(k).
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def get_row(row_index)
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(0..row_index).map {|num| combination(row_index, num) }
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end
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def combination(num1, num2)
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factorial(num1) / (factorial(num2) * factorial(num1 - num2))
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end
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def factorial(num)
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(1..num).inject(1) { |res, i| res * i }
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end
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row_index = 3
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print(get_row(row_index))
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# => [1,3,3,1]
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row_index = 0
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print(get_row(row_index))
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# => [1]
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row_index = 1
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print(get_row(row_index))
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# => [1,1]
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