/******************************************************************************* * My attempt on an algorithm for the game Mastermind which has been published * * first in 1971. The original game was about a pattern of 4 code pegs which * * were available in 6 different colors. Sadly the memorylimit exceeded when * * i tried it with 6 colors even after i changed all the int variables to * * short. So i decided to make a version with an adjustable amount of colors. * * You are free to take up the amount of colors on your pc. Max colors are 9. * * * * About the algorithm * * The used algorithm is based on Donald E. Knuth, who demonstrated(1977),that * * the code can be solved in 5 or fewer moves. It requires 4.478 moves on * * average. Its not the fastest algorithm, Kenji Koyama and Tony W. Lai found * * a method that required 4.340 moves on average. But that will maybe focused *` * another day. Cause my english is bad here is a link to wikipedia where you * * can read in short what the algorithm is doing. * * It is called the "five guess algorithm" * * https://en.wikipedia.org/wiki/Mastermind_(board_game) * * * * In the code is method to play the game by yourself, which is not possible * * on sololearn, because of the multiple needed inputs. So I marked it as a * * comment. * *******************************************************************************/ import java.util.concurrent.ThreadLocalRandom; //import java.util.Scanner; public class Minimind { static short colors = 3; static short cardinality = (short)Math.pow(colors, 4); public static void main(String[] args) { short secretCode = createRandomCode(); algorithm(secretCode); } static void algorithm(short secretCode) { //[x][0]=unused Codes, [x][1]=possible solutions short codes [][] = new short [cardinality][3]; short position=0; for (short i1=1;i1<=colors;i1++) { for (short i2=1;i2<=colors;i2++) { for (short i3=1;i3<=colors;i3++) { for (short i4=1;i4<=colors;i4++) { codes[position][0] = (short)(i1*1000+i2*100+i3*10+i4); codes[position][1] = codes[position][0]; position+=1; } } } } short guess = 1122; short countGuesses=1; do { //tests if there's only one possibility left and sets it for the next guess short countSolutions=0; for (short i = 0;imin) && (codes[i][0]!=0)) { min=codes[i][2]; } } for (short i=0;i0;i=i/10){ if ((guess / i) % 10==(secretCode / i) % 10) { hits+=1; } } return hits; } static short feedbackNumbers(short guess, short secretCode) { int hits=0; for (short i=1;i<=colors;i++) { int numberCountGuess = (Integer.toString(guess)).length() - (Integer.toString(guess)).replace(Integer.toString(i), "").length(); int numberCountSecretCode = Integer.toString(secretCode).length() - (Integer.toString(secretCode)).replace(Integer.toString(i), "").length(); if (numberCountGuess>0) { if (numberCountGuess <= numberCountSecretCode) { hits += numberCountGuess; } else { hits +=numberCountSecretCode; } } } return (short)(hits-feedbackPosition(guess, secretCode)); } }

Mastermind Algorithm