PAT 1054

a clever solution from other;
imaging the strictly dominate color stays at the first half of the area; then we just add the count until we reach another color, then we just subtract one until the end; then at last, we got zero; but we won't change the color we chose; and if that color splits randomly, it will not change the end result; because, at any time, we choose another color, and we will eventually choose back the right color;