public int findIndex(int[] nums, int begin, int end, int target) {
		if (begin > end)
			return -1;
		int mid = (end - begin) / 2 + begin;
		if (nums[mid] == target)
			return mid;
		else if (nums[mid] < target) {
			return findIndex(nums, mid + 1, end, target);
		} else
			return findIndex(nums, begin, mid - 1, target);
	}