message: Update clumsy-factorial.cpp
diff: // if N = 2 => N
  // if N = 3 => N + 3
  // if N = 4 => N + 2 + 1 = N + 3
  -// if N > 4 and N % 4 == 0 => N + 1 + (... = 0) + 5 - (4*3/2) + 1 = N + 1
  // if N > 4 and N % 4 == 1 => N + 1 + (... = 0) + 2 - 1 = N + 2
  // if N > 4 and N % 4 == 2 => N + 1 + (... = 0) + 3 - 2 * 1 = N + 2
  // if N > 4 and N % 4 == 3 => N + 1 + (... = 0) + 4 - 3 * 2 / 1 = N - 1
  +// if N > 4 and N % 4 == 0 => N + 1 + (... = 0) + 5 - (4*3/2) + 1 = N + 1
  class Solution {
  public:
  