private static void helper(int currentRow, int[] board, ArrayList<String[]> solutions) {

		if(currentRow == board.length) {
			buildSolution(board, solutions);
			return;
		}
		
		for (int i = 1; i <= board.length; i++) {
			board[currentRow] = i;
			
			if(valide(board, currentRow))
				helper(currentRow + 1, board, solutions);
		}
	}