受大佬启发： https://www.nowcoder.com/discuss/232739 线下跑几个例子暂时没发现问题...记录一下 #消消乐 def gravity(grid,visited):     # print('before:',grid)     for col in range(5):         cnt=0         for row in range(4,-1,-1):             if grid[row][col]=='x':                 cnt+=1             elif cnt>0:     ...