 

     

2019-02-11 17:13
  102
  0

  
 1                  —
A       B      C         
 2                              —
A   B   C    D   
 3           —
A   B   C   D    
4           —
A   B   C   D   
5                  —
A    B    C    D    
6     8          —
A   B    C         D     
 7           ——
A -1 -1 B  0  -2 C 1  1              — 
        
      1C 2A 3A 4A 5A



  
     
     