1011:Sticks（dfs）

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 int n,l;
 4 int lastN=-1;
 5 vector <int> length;
 6 int visit[1010];
 7 bool cmp(int a,int b) {
 8     return a>b;
 9 }
10 bool dfs(int r,int k) {
11     if(r==0&&k==0)return true;
12     if(k==0)k=l;
13     int startN=0;
14     if(k!=l)startN=lastN+1;
15     for(int i=startN; i<n; i++) {
16         if(!visit[i]&&length[i]<=k) {
17             if(i>0) {
18                 if(visit[i-1]==false&&length[i]==length[i-1])continue;
19             }
20             visit[i]=1;
21             lastN=i;
22             if(dfs(r-1,k-length[i]))return true;
23             else {
24                 visit[i]=0;
25                 if(length[i]==k||k==l)return false;
26             }
27         }
28     }
29     return false;
30 }
31 int main() {
32     int c,maxl=0;
33     while(cin>>n&&n!=0) {
34         maxl=0;
35         length.clear();
36         for(int i=0; i<n; i++) {
37             cin>>c;
38             length.push_back(c);
39             maxl+=length[i];
40         }
41         sort(length.begin(),length.end(),cmp);
42         for(l=length[0]; l<=maxl/2; l++) {
43             if(maxl%l)continue;
44             memset(visit,0,sizeof(visit));
45             if(dfs(n,l)) {
46                 cout<<l<<endl;
47                 break;
48             }
49 
50         }
51         if(l>maxl/2)cout<<maxl<<endl;
52     }
53 
54     return 0;
55 }