using System.Collections.Generic;
using System.Linq;

namespace TextAnalysis
{
    static class FrequencyAnalysisTask
    {
        public static Dictionary<string,string> CreateKey(List<string> sentence, int i)
        {
            return new Dictionary<string, string> {[sentence[i]] = sentence[i + 1]};
        }
        public static Dictionary<string, string> GetMostFrequentNextWords(List<List<string>> text)
        {
            var result = new Dictionary<string, string>();
            var inGram = new Dictionary<string,string>();
            var gramCount = new Dictionary<Dictionary<string, string>, int>();
            foreach (var sentence in text.Where(sentence => sentence.Count > 1))
            {
                for (var i = 0; i < sentence.Count - 1; i++)
                {
                    var gg = CreateKey(sentence, i);
                    if (!gramCount.ContainsKey(gg))
                        gramCount[gg] = 1;
                    else
                        gramCount[gg]++;
                }
            }
            return result;
        }
    }
}