basic-computer-games/48_High_IQ/java/src/HighIQ.java

import java.io.PrintStream;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

public class HighIQ {

    private Map<Integer,Boolean> board;
    private PrintStream out;
    private Scanner scanner;

    public HighIQ() {
        out = System.out;
        scanner = new Scanner(System.in);
        board = new HashMap<>();

        //Set of all locations to put initial pegs on
        int[] locations = new int[]{
                13, 14, 15, 22, 23, 24, 29, 30, 31, 32, 33, 34, 35, 38, 39, 40, 42, 43, 44, 47, 48, 49, 50, 51, 52, 53, 58, 59, 60, 67, 68, 69
        };

        for (int i : locations) {
            board.put(i, true);
        }

        board.put(41, false);
    }

    public boolean move() {
        System.out.println("MOVE WHICH PIECE");
        int from = scanner.nextInt();

        //using the getOrDefault, which will make the statement false if it is an invalid position
        if(!board.getOrDefault(from,false)) {
            return false;
        }

        System.out.println("TO WHERE");
        int to = scanner.nextInt();

        if(board.getOrDefault(to,true)) {
            return false;
        }

        //Do nothing if they are the same
        if(from == to) {
            return true;
        }

        //using the difference to check if the relative locations are valid
        int difference = Math.abs(to - from);
        if(difference != 2 && difference != 18) {
            return false;
        }

        //check if there is a peg between from and to
        if(!board.getOrDefault((to + from) / 2,false)) {
            return false;
        }

        return true;
    }

    public void play() {
        do {
            do {
                while(!move()) {
                    System.out.println("ILLEGAL MOVE, TRY AGAIN...");
                }
            } while(!isGameFinished());
            
            int pegCount = 0;
            for(Integer key : board.getKeySet()) {
                if(board.getOrDefault(key,false)) {
                    pegCount++;
                }
            }
        
            out.println("YOU HAD " + pegCount + " PEGS REMAINING");
        
            if(pegCount == 1) {
                out.println("BRAVO!  YOU MADE A PERFECT SCORE!");
                out.println("SAVE THIS PAPER AS A RECORD OF YOUR ACCOMPLISHMENT!");
            }
            
        } while(playAgain());
    }

    private boolean playAgain() {
        out.println("PLAY AGAIN (YES OR NO)");
        return scanner.nextLine().toLowerCase().equals("yes");
    }
    
    
    public boolean isGameFinished() {
        for(Integer key : board.getKeySet()) {
            if(board.get(key)) {
                //Spacing is either 1 or 9
                for(int space = 1; space <= 9; space += 8) {
                    //Next val is the next spot, prev and next after are the two spots where the peg would go if a move was possible
                    Boolean nextVal = board.get(key + space);
                    Boolean prevAfter = board.get(key - space);
                    Boolean nextAfter = board.get(key + space * 2);
                    
                    if(nextVal != null && nextVal) {
                        if((prevAfter != null && !prevAfter) || (nextAfter != null && !nextAfter)) {
                            return false;
                        }
                    }
                    
                }
            }
                
        }
        return true;
    }

    public void printBoard() {
        for(int i = 0; i < 7; i++) {
            for(int j = 11; j < 18; j++) {
                out.print(getChar(j + 9 * i));
            }
            out.println();
        }
    }
    
    private char getChar(int position) {
        Boolean value = board.get(position);
        if(value == null) {
            return ' ';
        } else if(value) {
            return '!';
        } else {
            return 'O';
        }
    }
}