查找

二分法查找

适用于数组已经从大到小排序

	public static int binarySearch(int[] data, int key) {
		int begin = 0;
		int end = data.length - 1;
		int mid;

		while (begin <= end) {
			mid = (begin + end) / 2;
			if (data[mid] == key) {
				return mid;
			} else if (data[mid] < key) {
				begin = mid + 1;
			} else {
				end = mid - 1;
			}

		}
		return -1;
	}