private void upHeapify(int c) {
			for (int p = (c - 1) / 2; c != 0 && distance[c] > distance[p]; c = p, p = (c - 1) / 2) {
				Object pData = data[p];
				double pDist = distance[p];
				data[p] = data[c];
				distance[p] = distance[c];
				data[c] = pData;
				distance[c] = pDist;
			}
		}