Method findSquare

java/Chapter 18/Question18_11/QuestionEff.java:21–38

(int[][] matrix)

	}
	
	public static Subsquare findSquare(int[][] matrix){
		assert(matrix.length > 0);
		for (int row = 0; row < matrix.length; row++){
			assert(matrix[row].length == matrix.length);
		}
		
		SquareCell[][] processed = processSquare(matrix);
		
		int N = matrix.length;
		
		for (int i = N; i >= 1; i--) {
			Subsquare square = findSquareWithSize(processed, i);
			if (square != null) {
				return square;
			}
		}
		return null;
	}	

	private static boolean isSquare(SquareCell[][] matrix, int row, int col, int size) {
		SquareCell topLeft = matrix[row][col];