HackerRank BattleShip Code Solution

HackerRank BattleShip Code Solution

Problem Name – BattleShip
Problem Link –  BattleShip
Level – Artificial Intelligence

Java Code

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Random;
import java.util.Scanner;

public class Battleship {
 public static void main(String[] args) {
  Scanner scn = new Scanner(System.in);
  String out = scn.nextLine();

  if (out.equals("INIT")) {
   System.out.println("3 0");
   System.out.println("9 9");
   System.out.println("6 4:6 5");
   System.out.println("3 7:4 7");
   System.out.println("7 7:7 9");
   System.out.println("1 5:1 8");
   System.out.println("3 2:7 2");
  } else {
   String[] board = new String[10];
   @SuppressWarnings("unused")
   boolean printed = false;

   for (int i = 0; i < 10; i++) {
    board[i] = scn.nextLine();
   }

   File fileName = new File("myfile.txt");

   if (!fileName.exists()) {
    try {
     fileName.createNewFile();
     FileWriter fileWrite = new FileWriter(fileName);
     BufferedWriter bufferedWriter = new BufferedWriter(
       fileWrite);
     ArrayList<Integer> moves = getRandom(board);
     int x = moves.get(0);
     int y = moves.get(1);
     bufferedWriter.write(x + " " + y);
     bufferedWriter.close();
     System.out.println(x + " " + y);
    } catch (IOException e) {
    }
   } else {
    try {
     byte[] buffer = new byte[100];
     FileInputStream inputStream = new FileInputStream(fileName);
     @SuppressWarnings("unused")
     int readLines = -1;
     String last_move = "";

     while ((readLines = inputStream.read(buffer)) != -1) {
      last_move = new String(buffer);
     }

     inputStream.close();
     int x = Character.getNumericValue(last_move.charAt(0));
     int y = Character.getNumericValue(last_move.charAt(2));

     if (board[x].charAt(y) == 'h') {
      if (x + 1 < 10 && board[x + 1].charAt(y) == 'h') {
       for (int i = 1; i < 9 - x; i++) {
        if (x - i >= 0 && board[x - i].charAt(y) == '-') {
         x -= i;
         break;
        } else if (x - i >= 0
          && board[x - i].charAt(y) == 'm') {
         break;
        }
       }

       for (int i = 1; i < 9 - x; i++) {
        if (x + i < 10 && board[x + i].charAt(y) == '-') {
         x += i;
         break;
        } else if (x + i < 10
          && board[x + i].charAt(y) == 'm') {
         break;
        }
       }
      } else if (x - 1 >= 0 && board[x - 1].charAt(y) == 'h') {
       for (int i = 1; i < 9 - x; i++) {
        if (x - i >= 0 && board[x - i].charAt(y) == '-') {
         x -= i;
         break;
        } else if (x - i >= 0
          && board[x - i].charAt(y) == 'm') {
         break;
        }
       }

       for (int i = 1; i < 9 - x; i++) {
        if (x + i < 10 && board[x + i].charAt(y) == '-') {
         x += i;
         break;
        } else if (x + i < 10
          && board[x + i].charAt(y) == 'm') {
         break;
        }
       }
      } else if (y + 1 < 10 && board[x].charAt(y + 1) == 'h') {
       for (int i = 1; i < 9 - y; i++) {
        if (y - i >= 0 && board[x].charAt(y - i) == '-') {
         y -= i;
         break;
        } else if (y - i >= 0
          && board[x].charAt(y - i) == 'm') {
         break;
        }
       }

       for (int i = 1; i < 9 - y; i++) {
        if (y + i < 10 && board[x].charAt(y + i) == '-') {
         y += i;
         break;
        } else if (y + i < 10
          && board[x].charAt(y + i) == 'm') {
         break;
        }
       }
      } else if (y - 1 >= 0 && board[x].charAt(y - 1) == 'h') {
       for (int i = 1; i < 9 - y; i++) {
        if (y - i >= 0 && board[x].charAt(y - i) == '-') {
         y -= i;
         break;
        } else if (y - i >= 0
          && board[x].charAt(y - i) == 'm') {
         break;
        }
       }

       for (int i = 1; i < 9 - y; i++) {
        if (y + i < 10 && board[x].charAt(y + i) == '-') {
         y += i;
         break;
        } else if (y + i < 10
          && board[x].charAt(y + i) == 'm') {
         break;
        }
       }
      } else {
       ArrayList<Integer> moves = getRemainingHit(board);
       x = moves.get(0);
       y = moves.get(1);
      }
     } else {
      ArrayList<Integer> moves = getRemainingHit(board);
      x = moves.get(0);
      y = moves.get(1);
     }

     while (board[x].charAt(y) != '-') {
      ArrayList<Integer> moves = getRandom(board);
      x = moves.get(0);
      y = moves.get(1);
     }

     fileName.createNewFile();
     FileWriter fileWrite = new FileWriter(fileName);
     BufferedWriter bufferedWriter = new BufferedWriter(
       fileWrite);
     bufferedWriter.write(x + " " + y);
     bufferedWriter.close();
     System.out.println(x + " " + y);
    } catch (IOException e) {
    }
   }
  }
 }

 private static ArrayList<Integer> getRemainingHit(String[] board) {
  ArrayList<Integer> to_return = new ArrayList<Integer>();
  boolean added = false;

  for (int x = 0; x < 10; x++) {
   for (int y = 0; y < 10; y++) {
    if (board[x].charAt(y) == 'h') {
     if (x - 1 >= 0 && board[x - 1].charAt(y) == '-') {
      to_return.add(x - 1);
      to_return.add(y);
      added = true;
     } else if (x + 1 < 10 && board[x + 1].charAt(y) == '-') {
      to_return.add(x + 1);
      to_return.add(y);
      added = true;
     } else if (y - 1 >= 0 && board[x].charAt(y - 1) == '-') {
      to_return.add(x);
      to_return.add(y - 1);
      added = true;
     } else if (y + 1 < 10 && board[x].charAt(y + 1) == '-') {
      to_return.add(x);
      to_return.add(y + 1);
      added = true;
     }
    }

    if (added) {
     return to_return;
    }
   }
  }

  return getRandom(board);
 }

 private static ArrayList<Integer> getRandom(String[] board) {
  ArrayList<Integer> to_return = new ArrayList<Integer>();
  Random ran = new Random();
  int x = 0;
  int y = 0;

  do {
   x = ran.nextInt(10);
   y = ran.nextInt(10);
  } while (board[x].charAt(y) != '-');

  to_return.add(x);
  to_return.add(y);

  return to_return;
 }
}

Output: 

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