import java.util.ArrayList;

// You should not need to change any code in this class. // // You may find it useful to read the comments and to see what // methods exist in the class public class Grid { private final int ROWS = 10; private final int COLUMNS = 10; private ArrayList ships = new ArrayList(); // If x, y contains an unhit ship, a point is set to true private ArrayList deadShips = new ArrayList(); // occupied: is a square occupied or not? // Using Ships instead of booleans because if a ship is // fired on, it is important to be able to ask that ship if // it has been sunk. If no ship is on the square, then // null is used. private Ship[][] occupied = new Ship[ROWS][COLUMNS]; // The array fired tells us the following about squares: // 0 = unfired upon // 1 = fired upon, with ship hit (* for display) // 2 = fired upon, with ship not hit (X for display) // 3 = fired upon, ship killed private int[][] fired = new int[ROWS][COLUMNS]; public Grid() { initGrid(); }

public int getRows() { return ROWS; } // number of cells in x direction public int getColumns() { return COLUMNS; } // number of cells in y direction public int getFired(int x, int y) { return fired[x][y]; } // 0, 1, 2, or 3 public ArrayList getShips() { return ships; } public ArrayList getDeadShips() { return deadShips; }

public void initGrid() { for (int x = 0; x < COLUMNS; x++) { for (int y = 0; y < ROWS; y++) { occupied[x][y] = null; // currently empty fired[x][y] = 0; // not yet attacked } } ships = new ArrayList(); deadShips = new ArrayList(); }

// Precondition: Point p has valid [x,y] public void fire(Point p) { Ship s = occupied[p.getX()][p.getY()]; if (s != null) { s.hit(p); System.out.println("BLAM! Direct hit at: " + p); if (s.isDead()) { deadShips.add(s); Point ll = s.getLowerLeft(); int x = ll.getX(); int y = ll.getY(); boolean dir = s.getDirection(); if (dir) { // horizontal for (int i = 0; i < s.length(); i++) { fired[x+i][y] = 3; } } else { for (int i = 0; i < s.length(); i++) { fired[x][y+i] = 3; } } ships.remove(s); System.out.println(s + " died horribly."); } else { fired[p.getX()][p.getY()] = 1; // fired at, ship hit } occupied[p.getX()][p.getY()] = null; } else { if (fired[p.getX()][p.getY()] == 0) { fired[p.getX()][p.getY()] = 2; // fired at, no ship } System.out.println("Whiff"); } s = null; }

public boolean gameOver() { return deadShips.size() == 5; }

// For printing the grid in the console for testing purposes public void print() { System.out.print("[ "); for (int y = occupied.length-1; y >= 0; y--) { System.out.print("( "); for (int x = 0; x < occupied[0].length; x++) { Ship occ = occupied[x][y]; if (occ != null) { System.out.print(occ.displayChar() + " "); } else { System.out.print("- "); } } if (y != 0) { System.out.println(")"); System.out.print(" "); } else { System.out.print(") "); } } System.out.println("]"); }

public String toString() { return "" + ships; }

// Returns true if p is a legal point on the Grid public boolean isValid(Point p) { return Utilities.between(p.getX(), 0, COLUMNS-1) && Utilities.between(p.getY(), 0, ROWS-1); } // Returns true if ship added successfully, false otherwise // The following assumes that the click location on the grid to place a // ship is the LOWER LEFT square on which the ship should be placed. // // Conditions for putting a ship on the grid: // 1. All parts of the ship must be on squares within the grid. // If the user tries to place a Battleship (length == 4) // horizontally at H5, it will fail because I5 and J5 exists, // but there is no K5 to put the other end of the ship. // 2. No other ship can occupy a square where the new ship is to be // placed. However, the user should be able to decide that an // original placement of a ship can be changed, so if an attempt // is made to place a Destroyer on the board, an existing Destroyer // would not be in conflict since it would be removed before the // new one is placed. public boolean addShip(int shipLength, Point p, boolean horiz, String name) { int x = p.getX(); int y = p.getY(); // Verify that the squares on which the ship is to be placed // are open and on the grid if (horiz) { // horizontal if (!(Utilities.between(x+shipLength-1, 0, COLUMNS-1) && Utilities.between(x, 0, COLUMNS-1) && Utilities.between(y, 0, ROWS-1))) return false; for (int i = 0; i < shipLength; i++) { Ship placedShip = occupied[x+i][y]; if (placedShip != null) { // If the conflicting ship is the same type as the // one we are trying to place, it is not actually // a conflict because we would remove it to do the // new placement. Ships of other types are a problem. // (We cannot put a submarine where a destroyer already is, // for example...) if (!placedShip.getName().equals(name)) { return false; } } } // Vertical placements similar to horizontal placements } else { // vertical if (!(Utilities.between(x, 0, COLUMNS-1) && Utilities.between(y, 0, ROWS-1) && Utilities.between(y+shipLength-1, 0, ROWS-1))) return false; for (int i = 0; i < shipLength; i++) { Ship placedShip = occupied[x][y+i]; if (placedShip != null) { if (!placedShip.getName().equals(name)) { return false; } } }

Randomize placement of the computer ships in the initComputerShips() method. (The code you received places the ships in fixed locations; that makes for a horribly boring game.) Ships need to be placed legally.

Play a game. The human always gets to go first.Until someone has destroyed all of the opponent's ships, do:

Human fires on computer by clicking on computer grid; there is a fireOnComputer() method in the Display class that is empty that you must fill in.

Computer fires on human; there is a fireOnHuman() method in the Display class that you must fill in.

fireOnHuman() results in the Human grid being attacked.

The computer should have a strategy that minimizes the number of attack attempts. The quality of the strategy and whether it works is what matters.

This needs to be initiated in the mouseReleased() method.

You are not allowed to change any existing methods no matter how horribly written you might think they are unless given permission to do so. Those methods are to be treated as library routines. The methods you can change (and must change) are:

initComputerShips()in the Display class

fireOnComputer() in the Display class

fireOnHuman() in the Display class (You may wish to consider adding parameters, too.)

mouseReleased() in the Display class (In case you want to send arguments to fireOnHuman()...)

paint() so you can show when the game is over

You can decide whether to create a Computer class that extends Player and contains the strategy for the computer (which makes the most sense object-wise) or just to write that code as additional methods in the Display class. I personally think that it will be easier to think about this problem in an object-oriented manner, meaning that I would create a Computer class, but whatever works for you is fine.

You may write whatever helper methods you want.