红包算法——最大最小值范围

  private static Random rd = new Random();
        public int GetRandomClaimAmount(int leftValue, int leftNums, int minValue, int maxValue)
        {
            int randomValue = 0;
            if (minValue <= 0)
            {
                minValue = 1;
            }
            int avgMaxValue = ((leftValue - (leftNums * minValue)) / leftNums) * 2;//保证至少都有最小值，然后在剩下的值里面随机
            if (maxValue > 0&&maxValue>=minValue)
            {
                avgMaxValue = (maxValue - minValue) < avgMaxValue ? (maxValue - minValue) : avgMaxValue;
            }
            if (leftNums == 1)//最后一次
            {
                if (maxValue > 0&&maxValue>=minValue)
                {
                    if (leftValue <= maxValue)
                    {
                        randomValue = leftValue;
                    }
                    else
                    {
                        avgMaxValue = maxValue - minValue;
                        randomValue = rd.Next(0, avgMaxValue)+minValue;
                    }
                }
                else
                {
                    randomValue = leftValue;
                }
            }
            else
            {
                randomValue = rd.Next(0, avgMaxValue);
                randomValue += minValue;
            }
            return randomValue;
        }