MergeIntervals.cs

/**
 * Definition for an interval.
 * public class Interval {
 *     public int start;
 *     public int end;
 *     public Interval() { start = 0; end = 0; }
 *     public Interval(int s, int e) { start = s; end = e; }
 * }
 */
public class Solution {
        public IList<Interval> Insert(IList<Interval> intervals, Interval newInterval)
        {
            var result = new List<Interval>();
            foreach (var item in intervals)
            {
                if (newInterval.start > item.end)
                {
                    result.Add(item);
                }
                else if (newInterval.end < item.start)
                {
                    result.Add(newInterval);
                    newInterval = item;
                }
                else if (item.end >= newInterval.start || item.start <= newInterval.end)
                {
                    newInterval = new Interval(Math.Min(item.start, newInterval.start), Math.Max(newInterval.end, item.end));
                }
            }

            result.Add(newInterval);

            return result;
        }
}