Quick Answer
Granulated sugar does not use the same grams-to-cups value as every other ingredient. Using a practical US cup reference, 201 grams of granulated sugar is about 1 cup.
That means 100 grams of granulated sugar is about 0.5 cups, while 200 grams is about 0.99 cups.
Granulated sugar settles densely, so cup values are usually heavier than flour for the same volume.