OOP 3

using System.Collections.Generic;

namespace TextAnalysis
{
    static class TextGeneratorTask
    {
        public static string ContinuePhrase(
            Dictionary<string, string> nextWords,
            string phraseBeginning,
            int wordsCount)
        {
            if (wordsCount == 0) return phraseBeginning;
            int counter = 0;
            string firstWord = "";
            string secondWord = "";
            for (int i = phraseBeginning.Length - 1; i >= 0; i--)
            {
                if (phraseBeginning[i] == ' ')
                {
                    counter++;
                    continue;
                }
                if (counter == 2) break;
                if (counter == 0) firstWord = phraseBeginning[i] + firstWord;
                if (counter == 1) secondWord = phraseBeginning[i] + secondWord;
            }
            for (int i = 0; i < wordsCount; i++)
            {
                if (nextWords.ContainsKey(secondWord + " " + firstWord))
                {
                    string buf = nextWords[secondWord + " " + firstWord];
                    secondWord = firstWord;
                    firstWord = buf;
                    phraseBeginning += " " + buf;
                }
                else if (nextWords.ContainsKey(firstWord))
                {
                    secondWord = firstWord;
                    firstWord = nextWords[firstWord];
                    phraseBeginning += " " + firstWord;
                }
                else break;
            }
            return phraseBeginning;
        }
    }
}