message: Update complement-of-base-10-integer.cpp
diff: class Solution {
  public:
  int bitwiseComplement(int N) {
  - int X = 1;
  - while (N > X) {
  - X = X * 2 + 1;
  + int mask = 1;
  + while (N > mask) {
  + mask = mask * 2 + 1;
  }
  - return X - N;
  + return mask - N;
  }
  };
  