public class Solution {

    public int FindMinDifference(IList<string> timePoints) {

        var ary = new int[ * ];

            foreach (var time in timePoints)

            {

                var tp = time.Split(':');

                var hour = tp[];

                var minute = tp[];

                var h = Convert.ToInt32(hour[].ToString()) *  + Convert.ToInt32(hour[].ToString());

                var m = Convert.ToInt32(minute[].ToString()) *  + Convert.ToInt32(minute[].ToString());

                var index = h *  + m;

                if (ary[index] == )

                {

                    return ;

                }

                else

                {

                    ary[index] = ;

                }

            }

            var min = int.MaxValue;

            bool first = true;

            var firstNum = int.MaxValue;

            var lastNum = int.MinValue;

            var pre = ;

            for (int i = ; i < ary.Length; i++)

            {

                if (ary[i] == )

                {

                    if (first)

                    {

                        pre = i;

                        first = false;

                        firstNum = i;

                        continue;

                    }

                    var diff = Math.Abs(i - pre);

                    if (diff >  / )

                    {

                        diff =  - diff;

                    }

                    if (min > diff)

                    {

                        min = diff;

                    }

                    pre = i;

                    lastNum = i;

                }

            }

            min = Math.Min(min, ( *  - lastNum + firstNum));

            return min;

    }

}