using System;

using System.Linq;

using System.Collections.Generic;

using System.Text.RegularExpressions;

​

public class Program

{

    static bool IsDanger1(string body, string dictionary, char separator)

    {

        var dict = new Dictionary<string,bool>();

        var last = 0;

        for(int i=0; i<dictionary.Length; i++) {

            if (dictionary[i] == separator) {

                if (last < i) {

                    var key = dictionary.Substring(last, i-last);

                    dict[key] = true;

                }

                last = i+1;

            }

        }

        if (last < dictionary.Length) {

            var key = dictionary.Substring(last);

            dict[key] = true;

        }

        last = 0;

        for(int i=0; i<body.Length; i++) {

            var c = body[i];

            if (!char.IsLetter(c)) {

                if (last < i) {

                    var key = body.Substring(last, i-last);

                    if (dict.ContainsKey(key)) {

                        return true;

                    }

                }

                last = i+1;

            }

        }

        if (last < body.Length) {

            var key = body.Substring(last);

            if (dict.ContainsKey(key)) {

                return true;

            }

        }

​

        return false;

    }

    static bool IsDanger2(string body, string dictionary, char separator)

    {

        var pattern = dictionary.Replace(separator, '|');

        pattern = "\\b(" + pattern + ")\\b";

        var re = new Regex(pattern);

        return re.IsMatch(body);

    }

    static bool IsDanger3(string body, string dictionary, char separator)

    {

        var words = dictionary.Split(',');

        var word = string.Empty;        

        var wordLength = 0;

        for(int i=0; i<body.Length; i++) {

            var c = body[i];

            if (char.IsLetter(c)) {

                wordLength++;

                continue;

            }

            if (wordLength > 0) {

                word = body.Substring(i-wordLength, wordLength);

                if (words.Any(o => o == word)) {

                    return true;

                }

            }

            wordLength = 0;

        }

        if (wordLength > 0) {

            word = body.Substring(body.Length-wordLength, wordLength);

            if (words.Any(o => o == word)) {

                return true;

            }

        }

        return false;

    }

​

    struct Letter {

        public char C;

        public bool IsEnd;

        public Letter(char c, bool isEnd)

        {

            C = c;

            IsEnd = isEnd;

        }

    }

    static bool IsDanger4(string body, string dictionary, char separator)

    {

        var n = 0;

        var places = new List<List<Letter>>();

        for(int i=0; i<dictionary.Length; i++) {

            var c = dictionary[i];

            if (c == separator) {

                n = 0;

                continue;

            }

            if (places.Count() <= n) {

                places.Add( new List<Letter>() );

            }

            if (!places[n].Any(o => o.C == c)) {

                var isEnd = i == dictionary.Length-1 || dictionary[i+1] == separator;

                //Console.WriteLine("[{4}] [{0}] '{1}' [{2}] {3}", i, c, dictionary.Length - 1, isEnd, n);

                var letter = new Letter(c, isEnd);

                places[n].Add(letter);

            }

            n++;

        }

        var exists = false;

        var wordLength = 0;

        for(int i=0; i<body.Length; i++) {

            var c = body[i];

            if (char.IsLetter(c)) {

                //Console.Write(" [{0}] IsLetter('{1}')", wordLength, c);

                if (exists || wordLength == 0) {

                    //Console.Write(" {0} ", exists);

                    exists = places.Count() > wordLength;

                    //Console.Write(" {0} ", exists);

                    if (exists) {

                        var isEnd = i == body.Length-1 || !char.IsLetter(body[i+1]);

                        //Console.Write(" isEnd:{0} ", isEnd);

                        exists = places[wordLength].Any(o => o.C == c && o.IsEnd == isEnd);

                    }

                }

                //Console.WriteLine();

                wordLength++;

                continue;

            }

            if (exists) {

                break;

            }

            wordLength = 0;

        }

        return exists;

    }

​

    public static void Main()

    {

        // https://www.ted.com/talks/amy_cuddy_your_body_language_shapes_who_you_are/transcript

        string body1 = "So I want to start by offering you a free no-tech life hacks1";

        string body2 = "So I want to start by offering you a free no-tech life hack";

        string dictionary = "test,t,tos,tosp,lif,hacks";

        char separator = ',';

​

        bool b1 = IsDanger1(body1, dictionary, separator);

        bool b2 = IsDanger1(body2, dictionary, separator);

        Console.WriteLine("{0} : {1} : {2}", "IsDanger1", b1, b2);

        b1 = IsDanger2(body1, dictionary, separator);

        b2 = IsDanger2(body2, dictionary, separator);

        Console.WriteLine("{0} : {1} : {2}", "IsDanger2", b1, b2);

        b1 = IsDanger3(body1, dictionary, separator);

        b2 = IsDanger3(body2, dictionary, separator);

        Console.WriteLine("{0} : {1} : {2}", "IsDanger3", b1, b2);

        b1 = IsDanger4(body1, dictionary, separator);

        b2 = IsDanger4(body2, dictionary, separator);

        Console.WriteLine("{0} : {1} : {2}", "IsDanger4", b1, b2);

    }

}

​