[Dynamic Planning] [memory-based search] computing of codevs 1011 in 2001 noip National League popularity Group

If the answer is F (N), we can obviously solve it recursively:

F (n) = F (1) + F (2) + ...... + F (n/2 ).

But n = 1000, it will obviously time out.

There may be at most N states, which have undergone a large number of repeated computations, so they can be remembered to reduce unnecessary computations.

1 # include <cstdio> 2 using namespace STD; 3 int N; 4 long memory [1001]; 5 long F (INT cur) 6 {7 if (memory [cur]) return memory [cur]; 8 long res = 1; 9 for (INT I = 1; I <= (cur> 1); I ++) RES + = f (I); 10 return memory [cur] = res; 11} 12 INT main () 13 {14 scanf ("% d", & N); 15 memory [1] = 1; 16 printf ("% LLD \ n", F (n )); 17 return 0; 18}

 

[Dynamic Planning] [memory-based search] computing of codevs 1011 in 2001 noip National League popularity Group