Short Problem Definition:

Find the minimal perimeter of any rectangle whose area equals N.

Link

MinPerimeterRectangle

Complexity:

expected worst-case time complexity is O(sqrt(N))

expected worst-case space complexity is O(1).

Execution:

Trivial search for the largest prime.

Solution:

import math
def solution(N):
    if N <= 0:
      return 0
  
    for i in xrange(int(math.sqrt(N)), 0, -1):
        if N % i == 0:
            return 2*(i+N/i)
            
    raise Exception("should never reach here!")