MinAvgTwoSlice【★★★★★】

        /// <summary>
        /// Solution
        /// 100/100
        /// </summary>
        /// <param name="A"></param>
        /// <returns></returns>
        public int solution(int[] A)
        {
            double avg = (A[0] + A[1]) / 2.0;
            int index = 0;
            for (int i = 1; i < A.Length - 2; i++)
            {
                if ((A[i] + A[i + 1]) / 2.0 < avg)
                {
                    index = i;
                    avg = (A[i] + A[i + 1]) / 2.0;
                }
                if ((A[i] + A[i + 1] + A[i + 2]) / 3.0 < avg)
                {
                    index = i;
                    avg = (A[i] + A[i + 1] + A[i + 2]) / 3.0;
                }
            }
            if ((A[A.Length - 2] + A[A.Length - 1]) / 2.0 < avg)
            {
                index = A.Length - 2;
                avg = (A[A.Length - 2] + A[A.Length - 1]) / 2.0;
            }
            return index;
        }