message: Update count-sorted-vowel-strings.cpp
diff: class Solution {
  public:
  int countVowelStrings(int n) {
  - return nCr(n + 4, 4); // H(5, n) = nCr(n+5-1, n) = nCr(n+4, 4)
  + return nCr(n + 4, 4); // H(5, n) = C(n+5-1, n) = C(n+4, 4)
  }
  private:
  