lesson10_2_MinPerimeterRectangle.rb

# An integer N is given, representing the area of some rectangle.

# The area of a rectangle whose sides are of length A and B is A * B, and the perimeter is 2 * (A + B).

# The goal is to find the minimal perimeter of any rectangle whose area equals N. The sides of this rectangle should be only integers.

# For example, given integer N = 30, rectangles of area 30 are:

# (1, 30), with a perimeter of 62,
# (2, 15), with a perimeter of 34,
# (3, 10), with a perimeter of 26,
# (5, 6), with a perimeter of 22.
# Write a function:

# def solution(n)

# that, given an integer N, returns the minimal perimeter of any rectangle whose area is exactly equal to N.

# For example, given an integer N = 30, the function should return 22, as explained above.

# Write an efficient algorithm for the following assumptions:

# N is an integer within the range [1..1,000,000,000].

def solution(n)
  a=Math.sqrt(n).floor.downto(1) {|c| break c if n%c == 0 }
  b=n/a
  2*(a+b)
end