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알고리즘 - Perimeter of squares in a rectangle

algorithm

문제

The drawing shows 6 squares the sides of which have a length of 1, 1, 2, 3, 5, 8. It’s easy to see that the sum of the perimeters of these squares is : 4 _ (1 + 1 + 2 + 3 + 5 + 8) = 4 _ 20 = 80

Could you give the sum of the perimeters of all the squares in a rectangle when there are n + 1 squares disposed in the same manner as in the drawing:

alternative text

#Hint: See Fibonacci sequence

#Ref: http://oeis.org/A000045

The function perimeter has for parameter n where n + 1 is the number of squares (they are numbered from 0 to n) and returns the total perimeter of all the squares.

예시

perimeter(5)  should return 80
perimeter(7)  should return 216

풀이과정

1. 피보나치 수열 함수를 생성
2. 피보나치 수열의 값들의 합에 4를 곱한 값을 리턴

code

function fibonacci(n) {
  var a = 1,
    b = 0,
    temp;

  while (n >= 0) {
    temp = a;
    a = a + b;
    b = temp;
    n--;
  }

  return b;
}

function perimeter(n) {
  var sum = 0;

  for (var i = n; i >= 0; i--) {
    sum += fibonacci(i);
  }

  var result = sum * 4;
  return result;
}
}

출처: www.codewars.com