やるだけ。
class ColorfulBricks {
public:
int countLayouts(string B)
{
map<char, int> cnt;
for (int i = 0; i < B.size(); ++i) {
++cnt[B[i]];
}
if (3 <= cnt.size()) return 0;
if (cnt.size() == 1) return 1;
if (cnt.size() == 2) return 2;
return -1;
}
};