// Vectorテンプレート

class Vector(T) {
private:
	T[] items;
	int count;
public:
	this() {
		clear();
	}
	T opIndex(int index) {
		return get(index);
	}
	void set(int index, T t) {
		assert(0 <= index && index < count);
		items[index] = t;
	}
	T[] opCast() {
		return items[0..count];
	}
	T get(int index) {
		assert(0 <= count && count < items.length);
		return items[index];
	}
	int size() {
		return count;
	}
	int capacity() {
		if (!items) {
			return 0;
		}
		return items.length;
	}
	void add(T t) {
		if (capacity() == size()) {
			int s = size() * 2;
			if (s == 0) {
				s++;
			}
			T[] newitems = new T[s];
			for (int i = 0; i < size(); i++) {
				newitems[i] = items[i];
			}
			items = newitems;
		}
		items[count] = t;
		count++;
	}
	bool empty() {
		return !items;
	}
	void clear() {
		count = 0;
		items = new T[16];
	}
}