Also, this class must contain the following constant:

public static final char EMPTY

This constant is set to a space $(\text{'}\text{'})$

The class must have the following public methods:

public LetterCrush$($int width, int height, String initial$)[$constructor$]$

The parameters width and height determine the grid's dimensions, and the

parameter initial is a String of capital letters used to initialize the two$-$dimensional

array grid.

Specifically, the number of rows in grid is given by the second parameter, and

the number of columns is given by the first parameter.

The first "width" characters of the String initial must be stored in the first row of

the grid, the second "width" characters of initial must be stored in the second row

of the grid, etc. If there are fewer characters in the String initial than the number

of entries in the grid, the remaining grid entries are set to EMPTY. If there are

more characters in initial than the number of entries in the grid, the extra

characters in initial are ignored. For example, if width $=4,$ height $=3,$ and initial $=$

"ABAABBAABA", then the first row of grid will store the characters $A,B,A,$ and

$A$; the second row of grid will store $B,B,A,$ and $A,$ and the last row of grid will

store B$,$ A$,$ and two spaces.

public String toString$()$

Returns a String representing the characters stored in grid in a format that is

easy to read, that exactly matches the format given below.

$($new LetterCrush$(4,3,$"AACADBBDCD"$)).$toString$()$ must return

"LetterCrush

$|AACA|0$

$|$DBBD$|1$

$|$CD $12$

$+0123+$

Note the row number at the end of the $2^{nd}$ to $4^{th}$ lines, and the column numbers in

the last row. The column indices will always be one$-$digit values $($grids with widths

greater than nine will not be tested$).$

public boolean isStable$()$

Returns false if there is any position in grid where a non$-$EMPTY character is

above an EMPTY character $($a grid entry with a smaller row than a grid entry with

a larger row in the same column $-$ thus, for the example given above in the

description of the toString$()$ method, isStable$()$ would return false$).$

Otherwise, returns true.