That was my first thought as well. My answer would have been something along the lines of, "Given my domain knowledge of eggs and sidewalks, I can estimate that

That was my first thought as well. My answer would have been something along the lines of, "Given my domain knowledge of eggs and sidewalks, I can estimate that the egg will survive a fall of at most zero or one stories. Therefore the best algorithm is a linear search starting from the 0th floor."