Codeforces Round #191 (Div. 2) E题
状态压缩DP，算sum，本来是枚举的，结果TLE了。。
1 #include <iostream> 2 #include <cstring> 3 #include <cstdio> 4 #include <queue> 5 #include <cstdlib> 6 using namespace std; 7 #define MOD 1000000007 8 int p[10001]; 9 int hash[1<<24]; 10 int sum[1<<24]; 11 int k[3]; 12 int lowbit(int t) 13 { 14 return t&(-t); 15 } 16 int main() 17 { 18 int n,m,i,j; 19 scanf("%d",&n); 20 for(i = 0; i < n; i ++) 21 { 22 scanf("%d",&p[i]); 23 } 24 scanf("%d",&m); 25 for(i = 1; i <= m; i ++) 26 { 27 scanf("%d",&k[i]); 28 } 29 if(m == 1) k[2] = k[1]; 30 hash[0] = 1; 31 for(i = 0;i < n;i ++) 32 sum[1<<i] = p[i]; 33 for(i = 1; i < (1<<n); i ++) 34 { 35 sum[i] = sum[i-lowbit(i)] + sum[lowbit(i)]; 36 if(sum[i] == k[1]||sum[i] == k[2]) 37 continue; 38 for(j = i; j > 0; j -= lowbit(j)) 39 { 40 hash[i] += hash[i-lowbit(j)]; 41 if(hash[i] > MOD) 42 hash[i] -= MOD; 43 } 44 } 45 printf("%d\n",hash[(1<<n)-1]); 46 return 0; 47 }
