DailyProgrammer Easy Challenge: Falling Sand

package daily.challenge.sand;

import java.util.ArrayList;
import java.util.Scanner;

public class SandFall {

    public static String[][] grid; //Good Old 2D Arrays :D

    static Scanner in = new Scanner(System.in);
    static int gridX, gridY;
    static int steps = 0; //Track the Number of Updates
    static boolean settled = false; //Flag - Are all pieces of sand settled?
    static ArrayList<String> History = new ArrayList<String>();

    public static void main(String[] args){
        System.out.print("The Width and Height of the Map (X, Y): ");
        String str = in.nextLine();

        //How should the input be separated?
        String[] temp = (str.contains(", "))? str.split(", "):(!str.contains(","))?str.split(" "):str.split(",");

        gridX = Integer.parseInt(temp[0]);//String -> int (Readability)
        gridY = Integer.parseInt(temp[1]);//String -> int (Readability)
        grid = new String[gridX][gridY];

        System.out.println("Assemble Map (Items: '#' = Rock, '.' = Sand, 's' = Empty Space):");
        for(int y = 0; y< gridY; y++){
            for (int x = 0; x<gridX; x++){
                grid[x][y] = in.next(); //Item at x, y is the next typed submitted char
                if(grid[x][y].equalsIgnoreCase("s")) grid[x][y] = " ";
                //Due to Scanner taking input upon hitting "Enter"
                //I had to add a Space character, s, it does add a bit
                //of ease of use as well. Look at Usage
            }
        }

        //If Not Settled then Update
        while(!settled){
            update();
        }

        //Once Settled print the final grid once more
        System.out.println("\n\n\n");
        printGrid("");
        System.out.println("\nThe Sand has settled in "+steps+" steps...");
        printHistory();


    }
    static boolean cantSettle = false; //Changed to True if any piece of sand can still fall
    /** Update the position of the sand crystals according to the item below it.
     *  Updates ALL items in one step.*/
    public static void update(){
        cantSettle = false;
        steps++;
        for(int y = 0;y<gridY;y++){
            for(int x = 0; x<gridX; x++){
                if(grid[x][y].equalsIgnoreCase(".")){
                    if(y == gridY-1) settled = (cantSettle)?false:true; //Boundary Check
                    else if(grid[x][y+1].equalsIgnoreCase(" ")){ //Space Check
                        grid[x][y] = " "; grid[x][y+1] = ".";//Swap Places
                        settled = false;
                        cantSettle = true;
                        printGrid("Sand Drop at ("+x+", "+y+")");//Print New Grid
                        steps++;
                    }else if(grid[x][y+1].equalsIgnoreCase("#")){//Rock Check
                        settled = (cantSettle)?false:true; //If can Settle then Settle
                    }else if(grid[x][y+1].equalsIgnoreCase(".")){ //Sand Check
                        if(checkSandCollision(x,y)){ //Sand-Sand is Nuanced so pass to method
                            settled = (cantSettle)?false:true; //If is settled then check if you can settle.
                        }else{settled = false; cantSettle = true;} //If not settled then unsettle.
                    }
                }
            }
        }
    }

    /** Print the Grid with the Change (msg) */
    public static void printGrid(String msg){
        System.out.println(msg.toUpperCase()+"--------------------------------------");
        for(int y = 0;y< gridY; y++){
            if(y>0)System.out.println();
            for (int x = 0; x<gridX; x++){
                System.out.print(grid[x][y] + " ");
            }
        }
        System.out.println("\n"+msg.toUpperCase()+"--------------------------------------\n");
        if(!msg.isEmpty()) History.add(steps +". "+msg);
    }

    /** If sand is colliding with Sand, scan a few pieces below to see if it is done */
    public static boolean checkSandCollision(int x, int y){
        if(grid[x][y+1].equalsIgnoreCase(".")){
            if(y+1 == gridY-1 || y == gridY-1) return true;
            if(grid[x][y+2].equalsIgnoreCase(".")){
                return checkSandCollision(x, y+1);//Woo recursion!
            }else if(grid[x][y+2].equalsIgnoreCase("#")) return true;
            else if(grid[x][y+2].equalsIgnoreCase(" ")) return false;
            //If the item is on the boundary, the movement IS complete (true)
            //If the item below is a rock, say the movement IS complete (true)
            //If the item below is Sand, call this method with the new X and Y
            //If the item below is Air, say the movement is INCOMPLETE (false)
        }

        return true; //If called for no reason
                     //by accident then just return true
    }

    public static void printHistory(){ //Simple Prompting Method
        System.out.print("\nPrint History? (Y/N): ");
        in = new Scanner(System.in);
        String str = in.nextLine();
        if(str.equalsIgnoreCase("y")||str.equalsIgnoreCase("yes")){
            System.out.println("\n-----------------------------------------------------");
            System.out.println("SAND FALL HISTORY");
            System.out.println("-----------------------------------------------------");
            for(String s: History){
                System.out.println(s);
            }
            System.out.println("-----------------------------------------------------");

        }else if(!str.equalsIgnoreCase("n") && !str.equalsIgnoreCase("no")){
            System.out.println("Incorrect Input! \n");
            printHistory();
        }
    }

}


USAGE:

The Width and Height of the Map (X, Y): 5 12
Assemble Map (Items: '#' = Rock, '.' = Sand, 's' = Empty Space):
. . . . .
# # # s s
. # # s .
. # s # .
# s . s s
s s s # s
. # # s s
s # # s .
s . . # #
s s s s s
s s s s s
# . # s s

SAND DROP AT (1, 9)--------------------------------------
. . .
# # #   .
. # # . .
. #   #
#
    . #
  # #   .
  # #   .
      # #
    .
. .
# . #
SAND DROP AT (1, 9)--------------------------------------

SAND DROP AT (2, 9)--------------------------------------
. . .
# # #   .
. # # . .
. #   #
#
    . #
  # #   .
  # #   .
      # #

. . .
# . #
SAND DROP AT (2, 9)--------------------------------------

SAND DROP AT (4, 2)--------------------------------------
. . .
# # #   .
. # # .
. #   # .
#
    . #
  # #   .
  # #   .
      # #

. . .
# . #
SAND DROP AT (4, 2)--------------------------------------

SAND DROP AT (4, 3)--------------------------------------
. . .
# # #   .
. # # .
. #   #
#       .
    . #
  # #   .
  # #   .
      # #

. . .
# . #
SAND DROP AT (4, 3)--------------------------------------

SAND DROP AT (4, 4)--------------------------------------
. . .
# # #   .
. # # .
. #   #
#
    . # .
  # #   .
  # #   .
      # #

. . .
# . #
SAND DROP AT (4, 4)--------------------------------------

SAND DROP AT (4, 1)--------------------------------------
. . .
# # #
. # # . .
. #   #
#
    . # .
  # #   .
  # #   .
      # #

. . .
# . #
SAND DROP AT (4, 1)--------------------------------------

SAND DROP AT (4, 2)--------------------------------------
. . .
# # #
. # # .
. #   # .
#
    . # .
  # #   .
  # #   .
      # #

. . .
# . #
SAND DROP AT (4, 2)--------------------------------------

SAND DROP AT (4, 3)--------------------------------------
. . .
# # #
. # # .
. #   #
#       .
    . # .
  # #   .
  # #   .
      # #

. . .
# . #
SAND DROP AT (4, 3)--------------------------------------


--------------------------------------
. . .
# # #
. # # .
. #   #
#       .
    . # .
  # #   .
  # #   .
      # #

. . .
# . #
--------------------------------------


The Sand has settled in 25 steps...

Print History? (Y/N): Y

-----------------------------------------------------
SAND FALL HISTORY
-----------------------------------------------------
1. Sand Drop at (3, 0)
2. Sand Drop at (4, 0)
3. Sand Drop at (3, 1)
4. Sand Drop at (4, 3)
5. Sand Drop at (2, 4)
6. Sand Drop at (4, 4)
7. Sand Drop at (4, 5)
8. Sand Drop at (0, 6)
9. Sand Drop at (0, 7)
10. Sand Drop at (0, 8)
11. Sand Drop at (1, 8)
12. Sand Drop at (2, 8)
13. Sand Drop at (0, 9)
14. Sand Drop at (1, 9)
15. Sand Drop at (2, 9)
17. Sand Drop at (4, 2)
18. Sand Drop at (4, 3)
19. Sand Drop at (4, 4)
21. Sand Drop at (4, 1)
22. Sand Drop at (4, 2)
23. Sand Drop at (4, 3)
-----------------------------------------------------