TOJ 1135 Matrix Chain Multiplication

TOJ 1135 Matrix Chain Multiplication

很简单的题，给定N个矩阵，然后给出一系列运算式，用括号来限制运算，最后求一共进行了多少次乘法运算。
R(m,s) 和Q(s,n)相乘，要进行m*s*n次～
处理运算先后的时候，用栈实现，即后进先出就可以了。
Sample Input:

9
A 50 10
B 10 20
C 20 5
D 30 35
E 35 15
F 15 5
G 5 10
H 10 20
I 20 25
A
B
C
(AA)
(AB)
(AC)
(A(BC))
((AB)C)
(((((DE)F)G)H)I)
(D(E(F(G(HI)))))
((D(EF))((GH)I))
Sample Outout:
 
0
0
0
error
10000
error
3500
15000
40500
47500
15125
Code:


            
      
      
      

             
             
       
       
       #include 
             
       
       
       <
             
       
       
       iostream
             
       
       
       >
             
       
       
       
#include 
             
       
       
       <
             
       
       
       cstdio
             
       
       
       >
             
       
       
       
#include 
             
       
       
       <
             
       
       
       string
             
       
       
       >
             
       
       
       
#include 
             
       
       
       <
             
       
       
       map
             
       
       
       >
             
       
       
       

             
       
       
       using
             
       
       
        
             
       
       
       namespace
             
       
       
        std;


             
       
       
       struct
             
       
       
        Matrx{
        
             
       
       
       char
             
       
       
        id;
        
             
       
       
       int
             
       
       
        x,y;
}a[
             
       
       
       30
             
       
       
       ];
Matrx stack[
             
       
       
       100
             
       
       
       ];

             
       
       
       int
             
       
       
        main()
{
        
             
       
       
       int
             
       
       
        i,j,k,n,ans;
        
             
       
       
       bool
             
       
       
        flag;
        map
             
       
       
       <
             
       
       
       char
             
       
       
       ,
             
       
       
       int
             
       
       
       >
             
       
       
       mark;
        scanf(
             
       
       
       "
             
       
       
       %d
             
       
       
       "
             
       
       
       ,
             
       
       
       &
             
       
       
       n);
        
             
       
       
       for
             
       
       
       (i 
             
       
       
       =
             
       
       
        
             
       
       
       1
             
       
       
       ;i 
             
       
       
       <=
             
       
       
        n; i
             
       
       
       ++
             
       
       
       ){
                cin 
             
       
       
       >>
             
       
       
        a[i].id;
                scanf(
             
       
       
       "
             
       
       
       %d%d
             
       
       
       "
             
       
       
       ,
             
       
       
       &
             
       
       
       a[i].x,
             
       
       
       &
             
       
       
       a[i].y);
                mark[a[i].id] 
             
       
       
       =
             
       
       
        i;
        }
        
             
       
       
       string
             
       
       
        str;
        
             
       
       
       while
             
       
       
       (cin
             
       
       
       >>
             
       
       
       str){
                ans 
             
       
       
       =
             
       
       
        
             
       
       
       0
             
       
       
       ; flag 
             
       
       
       =
             
       
       
        
             
       
       
       true
             
       
       
       ;
                
             
       
       
       int
             
       
       
        len 
             
       
       
       =
             
       
       
        str.length();
                
             
       
       
       int
             
       
       
        head,tail;
                head 
             
       
       
       =
             
       
       
        tail 
             
       
       
       =
             
       
       
        
             
       
       
       0
             
       
       
       ;
                
             
       
       
       for
             
       
       
       (i 
             
       
       
       =
             
       
       
        
             
       
       
       0
             
       
       
       ;i 
             
       
       
       <
             
       
       
       len; i
             
       
       
       ++
             
       
       
       ){
                        
             
       
       
       if
             
       
       
       (str[i] 
             
       
       
       ==
             
       
       
        
             
       
       
       '
             
       
       
       (
             
       
       
       '
             
       
       
       )
                                
             
       
       
       continue
             
       
       
       ;
                        
             
       
       
       else
             
       
       
        
             
       
       
       if
             
       
       
       (str[i] 
             
       
       
       ==
             
       
       
        
             
       
       
       '
             
       
       
       )
             
       
       
       '
             
       
       
       ){     
             
       
       
       //
             
       
       
       pop
             
       
       
       

             
       
       
                                       
             
       
       
       if
             
       
       
       (head 
             
       
       
       ==
             
       
       
        
             
       
       
       1
             
       
       
       )
                                        head 
             
       
       
       --
             
       
       
       ;
                                
             
       
       
       else
             
       
       
        
             
       
       
       if
             
       
       
       (head 
             
       
       
       >
             
       
       
        
             
       
       
       1
             
       
       
       ){
                                        
             
       
       
       int
             
       
       
        tx 
             
       
       
       =
             
       
       
        stack[head
             
       
       
       -
             
       
       
       2
             
       
       
       ].x;
                                        
             
       
       
       int
             
       
       
        ty 
             
       
       
       =
             
       
       
        stack[head
             
       
       
       -
             
       
       
       1
             
       
       
       ].y;
                                        
             
       
       
       if
             
       
       
       (stack[head
             
       
       
       -
             
       
       
       2
             
       
       
       ].y 
             
       
       
       !=
             
       
       
        stack[head
             
       
       
       -
             
       
       
       1
             
       
       
       ].x) flag 
             
       
       
       =
             
       
       
        
             
       
       
       false
             
       
       
       ;
                                        ans 
             
       
       
       +=
             
       
       
        stack[head
             
       
       
       -
             
       
       
       2
             
       
       
       ].x
             
       
       
       *
             
       
       
       stack[head
             
       
       
       -
             
       
       
       2
             
       
       
       ].y
             
       
       
       *
             
       
       
       stack[head
             
       
       
       -
             
       
       
       1
             
       
       
       ].y;
                                        head 
             
       
       
       -=
             
       
       
        
             
       
       
       2
             
       
       
       ;
                                        stack[head].x 
             
       
       
       =
             
       
       
        tx;
                                        stack[head
             
       
       
       ++
             
       
       
       ].y 
             
       
       
       =
             
       
       
        ty;
                                }

                        }
                        
             
       
       
       else
             
       
       
       {        
             
       
       
       //
             
       
       
        push
             
       
       
       

             
       
       
                                       stack[head
             
       
       
       ++
             
       
       
       ] 
             
       
       
       =
             
       
       
        a[mark[str[i]]];

                        }
                }
                
             
       
       
       if
             
       
       
       (
             
       
       
       !
             
       
       
       flag) printf(
             
       
       
       "
             
       
       
       error\n
             
       
       
       "
             
       
       
       );
                
             
       
       
       else
             
       
       
        printf(
             
       
       
       "
             
       
       
       %d\n
             
       
       
       "
             
       
       
       ,ans);
        }
}