Find saddle points in a matrix

output

Saddle point found at: [1, 3]
No saddle points found
Saddle point found at: [1, 3]

saddle_points.rb

module SaddlePoint
  class Matrix
    def initialize(array = [])
      @rows = array
    end
  
    def saddle_points
      saddle_points = []
      @rows.each_with_index do |row, column_index|
        max_row_value = row.max
      
        indicies(row, max_row_value).each do |row_index|
          min_column_value = extract_column(row_index).min
          saddle_points << { row: row_index, col: column_index } if max_row_value == min_column_value
        end
      end
      saddle_points
    end
  
    def indicies(array, value)
      indicies = []
      array.each_with_index do |v, i|
        indicies << i if v == value
      end
      indicies
    end

    def extract_column(index)
      @rows.collect do |row|
        row[index]
      end
    end
  end

  class Printer
    def initialize(array = [])
      @matrix = Matrix.new(array)
    end

    def print_saddle_points()
      cells = @matrix.saddle_points

      puts "No saddle points found" if cells.empty?

      cells.each do |cell|
        puts "Saddle point found at: [#{cell[:row]}, #{cell[:col]}]"
      end
    end
  end
end

arr1 = [[39, 43, 49, 29, 18], 
        [30, 47, 24, 29, 15], 
        [49, 50, 39, 20, 33], 
        [18, 38, 35, 32, 35], 
        [29, 44, 18, 34, 44]]

arr2 = [[50, 27, 36, 43, 39], 
        [36, 14, 35, 40, 19], 
        [20, 33, 48, 32, 40], 
        [41, 40, 15, 22, 19], 
        [21, 24, 24, 31, 18]]
        
arr3 = [[39, 43, 49, 29, 18], 
        [30, 47, 24, 29, 15], 
        [49, 50, 39, 20, 33], 
        [18, 38, 35, 32, 38], 
        [29, 44, 18, 34, 44]]

SaddlePoint::Printer.new(arr1).print_saddle_points
SaddlePoint::Printer.new(arr2).print_saddle_points
SaddlePoint::Printer.new(arr3).print_saddle_points