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vbrazo/rotate_a_matrix_90_degrees.rb

Last active August 24, 2019 18:34
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  1. vbrazo revised this gist Aug 24, 2019. 1 changed file with 1 addition and 1 deletion.
    2 changes: 1 addition & 1 deletion rotate_a_matrix_90_degrees.rb
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    Original file line number Diff line number Diff line change
    @@ -1,6 +1,6 @@
    #
    # Transpose a matrix
    # Make [[1,2,3],[4,5,6],[7,8,9]] becomes [[1,4,7], [2,5,8], [3,6,9]]
    # Make [[1,2,3], [4,5,6], [7,8,9]] becomes [[1,4,7], [2,5,8], [3,6,9]]
    #
    class Array
    def my_transpose
  2. vbrazo revised this gist Aug 24, 2019. No changes.
  3. vbrazo revised this gist Aug 24, 2019. 1 changed file with 1 addition and 1 deletion.
    2 changes: 1 addition & 1 deletion rotate_a_matrix_90_degrees.rb
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    Original file line number Diff line number Diff line change
    @@ -23,7 +23,7 @@ def my_reverse(array)

    array.each do
    reverse << array[i]
    i-=1
    i -= 1
    end

    reverse
  4. vbrazo revised this gist Aug 24, 2019. 1 changed file with 1 addition and 2 deletions.
    3 changes: 1 addition & 2 deletions rotate_a_matrix_90_degrees.rb
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    Original file line number Diff line number Diff line change
    @@ -46,5 +46,4 @@ def rotate90(array)
    2.5.1 :1736 > rotate90([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
    => [[7, 4, 1], [8, 5, 2], [9, 6, 3]]
    2.5.1 :1737 > rotate90([[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12], [13, 14, 15, 16]])
    => [[13, 9, 5, 1], [14, 10, 6, 2], [15, 11, 7, 3], [16, 12, 8, 4]]

    => [[13, 9, 5, 1], [14, 10, 6, 2], [15, 11, 7, 3], [16, 12, 8, 4]]
  5. vbrazo renamed this gist Aug 24, 2019. 1 changed file with 0 additions and 0 deletions.
    0 Rotate a matrix 90 degrees using Ruby → rotate_a_matrix_90_degrees.rb
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    File renamed without changes.
  6. vbrazo created this gist Aug 24, 2019.
    50 changes: 50 additions & 0 deletions Rotate a matrix 90 degrees using Ruby
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    Original file line number Diff line number Diff line change
    @@ -0,0 +1,50 @@
    #
    # Transpose a matrix
    # Make [[1,2,3],[4,5,6],[7,8,9]] becomes [[1,4,7], [2,5,8], [3,6,9]]
    #
    class Array
    def my_transpose
    size.times do |i|
    0.upto(i) do |j|
    self[i][j], self[j][i] = self[j][i], self[i][j]
    end
    end
    self
    end
    end

    #
    # Reverse array
    # Make [1,4,7] becomes [7,4,1]
    #
    def my_reverse(array)
    reverse = []
    i = -1

    array.each do
    reverse << array[i]
    i-=1
    end

    reverse
    end

    #
    # Rotate matrix 90
    #
    def rotate90(array)
    array = array.my_transpose
    array.map { |row| my_reverse(row) }
    end

    rotate90([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
    rotate90([[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12], [13, 14, 15, 16]])

    #
    # IRB console:
    #
    2.5.1 :1736 > rotate90([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
    => [[7, 4, 1], [8, 5, 2], [9, 6, 3]]
    2.5.1 :1737 > rotate90([[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12], [13, 14, 15, 16]])
    => [[13, 9, 5, 1], [14, 10, 6, 2], [15, 11, 7, 3], [16, 12, 8, 4]]