using System;

using System.Collections.Generic;

​

// LeetCode problem 205: Isomorphic Strings

// https://leetcode.com/problems/isomorphic-strings/

​

public class Program

{

    public static void Main()

    {

        //false test

        //string s = "foo";

        //string t = "bar";

        //true test

        string s = "egg";

        string t = "add";

        Program p = new();

        Console.WriteLine($"Are the strings isomorphic? [{IsIsomorphic(s,t)}] \n\r");

​

​

        bool IsIsomorphic(string s, string t) 

        {

            if (s.Length != t.Length) return false;

​

            Dictionary<char,char> map = new();

            char c = 'a';

​

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

            {

                if (map.ContainsKey(s[i]) && map.TryGetValue(s[i], out c))

                {

                    if (!c.Equals(t[i])) return false;

                }   

                else if (!map.ContainsValue(t[i])) 

                {

                    map.Add(s[i], t[i]);

                }

                else return false;

                Console.WriteLine($"map.Key(s[i]) = [{s[i]}] | map.GetValue(s[i]) = [{map.GetValueOrDefault(s[i])}] (...OR...) KEY (s[i]) = [{s[i]}] | VALUE (t[i]) = [{t[i]}] \n\r");

            } 

            return true;

        }

    }   

}