LetterBloxBot.cs

using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Threading;

namespace LetterBloxBot {
    class Program {
        // WinAPI:
        [DllImport("user32.dll")]
        static extern void keybd_event(byte bVk, byte bScan, uint dwFlags, UIntPtr dwExtraInfo);
        const uint KEYEVENTF_KEYUP = 0x0002;

        // Timings (tune this to change difficulty)
        const int TIME_DOWN = 1;
        const int TIME_UP = 1;

        const bool RANDOM = false;  // make it try words in a random order, or not.

        static void Main(string[] args) {
            Console.Write("What are the 6 letters? ");
            string letterPool = Console.ReadLine().Substring(0, 6).ToLower();
            Console.WriteLine("Go click on the game window in the next 2 seconds.");
            Thread.Sleep(2000);

            List<string> strings = new List<string>();
            for (int i = 6; i >= 3; i--)    // iterate backwards so we get the high-scoring words first
                strings.AddRange(Iterate(letterPool, i));

            if (RANDOM) {
                Random rand = new Random();
                while (strings.Count > 0) {
                    int i = rand.Next(strings.Count);
                    HackLine(strings[i]);
                    strings.RemoveAt(i);
                }
            }
            else {
                for (int i = 0; i < strings.Count; i++) {
                    HackLine(strings[i]);
                }
            }
        }

        static string[] Iterate(string letterPool, int depth) {
            List<string> words = new List<string>();

            int perm;
            int[] indices = new int[depth];

            for (perm = 0; perm < Math.Pow(letterPool.Length, depth); perm++) {

                // build the indices array
                int temp = perm;
                for (int i = 0; i < depth; i++) {
                    indices[i] = temp % letterPool.Length;
                    temp /= letterPool.Length;
                }

                // check if there are duplicate letters
                bool skip = false;
                for (int i = 0; i < depth; i++) {
                    for (int j = i + 1; j < depth; j++) {
                        if (indices[i] == indices[j])
                            skip = true;
                    }
                }
                if (skip)
                    continue;

                // construct the string
                string s = "";
                for (int i = 0; i < depth; i++)
                    s += letterPool[indices[depth - 1 - i]];

                // check to avoid redundancy, and add to the list
                if (!words.Contains(s))
                    words.Add(s);
            }
            return words.ToArray();
        }

        // print to console and use WinApi to convey it
        static void HackLine(string message) {
            Console.WriteLine(message);
            message += "\n";
            for (int i = 0; i < message.Length; i++) {

                int keycode = -1;
                if (message[i] >= 'a' && message[i] <= 'z')
                    keycode = (byte)(0x41 + message[i] - 'a');
                else if (message[i] == '\n')
                    keycode = 0x0D;

                if (keycode >= 0) {
                    keybd_event((byte)keycode, 0, 0, UIntPtr.Zero); // KEY_DOWN
                    Thread.Sleep(TIME_DOWN);
                    keybd_event((byte)keycode, 0, KEYEVENTF_KEYUP, UIntPtr.Zero); // KEY_UP
                    Thread.Sleep(TIME_UP);
                }
            }
        }
    }
}