TrafficCongestionDivTwo.cpp

struct TrafficCongestionDivTwo {
  long long theMinCars(int treeHeight) {
		int i;
		Int ans = 1LL;
		
		for (i = treeHeight; i >= 1; i -= 2) {
			ans += (Int) (pow(2, i) / 2);
		}
		
		if (treeHeight % 2 != 0) ans -= 1LL;
		
		return ans;
	}
};