Hex is always specific ordering, R > G > B. They're all 0 through F (16 digits). It gives you a "higher, lower, equals" on every digit. That means it's 6 cases

Hex is always specific ordering, R > G > B. They're all 0 through F (16 digits). It gives you a "higher, lower, equals" on every digit. That means it's 6 cases of binary searches, 2^4 = 16, so that's all you're going to need.