def  solution(input):     list_input = [i.strip().split(" ") for i in input]     for row in range(len(list_input)):         ori_row = [int(i) for i in list_input[row] if int(i)]         new_row = []         i = 0         while i < len(ori_row):             if i < len(ori_row)-1 and ori_row[i] == ori_row[i+1]:                 new_row.append(ori_row[i] * 2)                 i += 2             else:                 new_row.append(ori_row[i])                 i += 1         for i in range(len(list_input[row])):             if i < len(new_row):                 list_input[row][i] = new_row[i]             else:                 list_input[row][i] = 0     string = ""     for row in list_input:         for num in row:             string += str(num) + " "         string += "\n"     return string 2048的，数组那个没a