hdu 4277 2012长春赛区网络赛 dfs+hashmap ***

 1 #include<cstdio>
 2 #include<iostream>
 3 #include<algorithm>
 4 #include<cstring>
 5 #include<cmath>
 6 #include<queue>
 7 #include<map>
 8 using namespace std;
 9 #define MOD 1000000007
10 const int INF=0x3f3f3f3f;
11 const double eps=1e-5;
12 typedef long long ll;
13 #define cl(a) memset(a,0,sizeof(a))
14 #define ts printf("*****\n");
15 const int MAXN=1005;
16 int n,m,tt;
17 int sum=0,a[MAXN];
18 const int HASH = 1000007;
19 struct HASHMAP
20 {
21     int head[HASH],next[HASH],size;
22     int state[HASH][3];
23     int hash(int a,int b,int c)
24     {
25       return (((a*7+b)*7+c)*7)%HASH;　　//131
26     }
27     void init()
28     {
29         size = 0;
30         memset(head,-1,sizeof(head));
31     }
32     int insert(int a,int b,int c)
33     {
34         int h = hash(a,b,c);
35         for(int i = head[h]; i != -1;i = next[i])
36             if(a == state[i][0]&&b == state[i][1]&&c == state[i][2])
37             {
38                 return 1;
39             }
40         state[size][0]=a,state[size][1]=b,state[size][2]=c;
41         next[size] = head[h];
42         head[h] = size++;
43         return 0;
44     }
45 } H1;
46 bool check(int a1,int a2,int a3)
47 {
48     if(a1+a2>a3&&a1+a3>a2&&a2+a3>a1)   return 1;
49     else return 0;
50 }
51 void dfs(int a1,int a2,int a3,int pos)
52 {
53     if(a3>sum/3)    return;
54     if(pos>=n)
55     {
56         if(a1==0||a2==0||a3==0) return;
57         if(check(a1,a2,a3)&&a1>=a2&&a2>=a3)
58         {
59             H1.insert(a1,a2,a3);
60         }
61         return;
62     }
63     dfs(a1+a[pos],a2,a3,pos+1);
64     dfs(a1,a2+a[pos],a3,pos+1);
65     dfs(a1,a2,a3+a[pos],pos+1);
66 }
67 
68 int main()
69 {
70     int i,j,k,ca=1;
71     #ifndef ONLINE_JUDGE
72     freopen("1.in","r",stdin);
73     #endif
74     scanf("%d",&tt);
75     while(tt--)
76     {
77         H1.init();
78         sum=0;
79         scanf("%d",&n);
80         for(i=0;i<n;i++)    scanf("%d",a+i),sum+=a[i];
81         dfs(0,0,0,0);
82         printf("%d\n",H1.size);
83     }
84 }