DFS/poj 1011/hdu 1455 Sticks

 1 #include<cstdio>
 2 #include<algorithm>
 3 #include<cstring>
 4 using namespace std;
 5 int n,tot,ans;
 6 bool v[100];
 7 int a[100];
 8 bool cmp(int x,int y)
 9 {
10     return x>y;
11 }
12 bool dfs(int now,int dep,int ans,int len)
13 {
14     if (ans==(tot/len)) return true;
15     else if (now>len) return false;
16     else if (now==len) return dfs(0,1,ans+1,len);
17     else for (int i=dep;i<=n;i++)
18     {
19         if (v[i]!=1)
20         {
21             v[i]=1;
22             if (dfs(now+a[i],i+1,ans,len)) return true;
23             v[i]=0;
24             if (now==0) return false;
25         }
26     }
27     return false;
28 }
29 int main()
30 {
31     scanf("%d",&n);
32     while (n!=0)
33     {
34         tot=0;
35         memset(v,0,sizeof(v));
36         for (int i=1;i<=n;i++)
37         {
38             scanf("%d",&a[i]);
39             tot+=a[i];
40         }
41         sort(a+1,a+n+1,cmp);
42         for (int len=a[1];len<=tot;len++)
43             if (tot%len==0)
44             {
45                 ans=0;
46                 if (dfs(0,1,0,len))
47                 {
48                     printf("%d\n",len);
49                     break;
50                 }
51             }
52 
53         scanf("%d",&n);
54     }
55     return 0;
56 }