message: Update ambiguous-coordinates.cpp
diff: @@ -35,7 +35,7 @@ private:
  right.back() != '0') {
  string s;
  s += left;
  - s += (d < n ? "." : "");
  + s += (!right.empty() ? "." : "");
  s += right;
  result.emplace_back(move(s));
  }
  