Verify on server side

[dunghy7]

public bool Verify([FromBody] List<string> datas)
        {
            var value = JsonConvert.DeserializeObject<List<int>>(datas[0]);
            var sum = value.Sum();
            var avg = sum * 1.0 / value.Count;
            var stddev = value.Select(v => Math.Pow(v - avg, 2)).Sum() / value.Count;
            return stddev != 0;
        }

When slide image successful or unsuccessful, always return the number greater than 0