def checkSudoku(fName):
	sudokuNumbers = []
	with open(fName, 'r', encoding="utf-8") as f:
		for line in f:
			for char in line:
				if char.isnumeric():
					sudokuNumbers.append(int(char))

	sudokuRows = [sudokuNumbers[i:i + 9] for i in range(0, len(sudokuNumbers), 9)]
	sudokuColumns = [[] for i in range(9)]
	for row in sudokuRows:
		for i,col in enumerate(row):
			sudokuColumns[i].append(col)

	sudokuSubgrids = [[] for i in range(9)]
	offset = 0
	for i,row in enumerate(sudokuRows):
		if i % 3 == 0 and i != 0:
			offset += 3
		subgridparts = [row[x:x + 3] for x in range(0, len(row), 3)]
		for j, subgridpart in enumerate(subgridparts):
			for number in subgridpart:
				sudokuSubgrids[j+offset].append(number)

	sudokuSubgridRows = [sudokuSubgrids[i:i + 3] for i in range(0, len(sudokuSubgrids), 3)]

	illegalRows = []
	illegalCols = []
	illegalSubgrids = []
	
	for i,row in enumerate(sudokuRows):
		if len(row) != len(set(row)):
			illegalRows.append(str(i+1))

	for i,col in enumerate(sudokuColumns):
		if len(col) != len(set(col)):
			illegalCols.append(str(i+1))

	for x,subgridRow in enumerate(sudokuSubgridRows):
		for y,subgrid in enumerate(subgridRow):
			if len(subgrid) != len(set(subgrid)):
				illegalSubgrids.append(str([x+1, y+1]))

	if not illegalRows and not illegalCols and not illegalSubgrids:
		print("The sudoku solution is legal")
	else:
		if illegalRows:
			print("Illegal rows: {0}".format(' '.join(illegalRows)))
		if illegalCols:
			print("Illegal columns: {0}".format(' '.join(illegalCols)))
		if illegalSubgrids:
			print("Illegal subgrids: {0}".format(' '.join(illegalSubgrids)))