hoj1049 sticks

http://acm.hit.edu.cn/hoj/problem/view?id=1049

经典的深搜+剪枝题，

/*This Code is Submitted by billforum for Problem 1049 at 2012-01-31 17:05:44*/
#include <iostream>
#include <algorithm>

using namespace std;

struct point
{
        int num;
        int next;
};
point data[100];
bool visit[100];
int total,len,n;

bool cmp(point x,point y)
{
  return (x.num>y.num); 
}

bool dfs(int res,int next,int cpl)
{
        
        if(res==len)
        {
                res=0;
                cpl++;
                next=1;
        }
        if(cpl==total) return true;
        int i=next;

while(i<n)
        {
                if(visit[i])
                {
                        i++;
                        continue;
                }//if
                if(data[i].num+res<=len)
                {
                        visit[i]=1;
                        if(dfs(data[i].num+res,i+1,cpl)) return true;
                        visit[i]=0;//
                        if(res==0) break;//剪枝
                        if(res+data[i].num==len) break;//剪枝
                        i=data[i].next;
                        continue;
                }//if
                i++;
        }//while
        return false;
}

int main(int args,char** argv)
{
        int ind,id,sum;
        while(cin>>n&&n)
        {
                sum=0;
                for(int i=0;i<n;i++)
                {
                cin>>ind;
                data[i].num=ind;
                sum+=ind;
                visit[i]=0;
                }
                sort(data,data+n,cmp);
                id=0;
                while(id<n)
            {
                        int j=id+1;
                        while((data[j].num==data[id].num)&&j<n) j++;//j?=n
                        for(int i=id;i<j;i++)
                                data[i].next=j;
                        id=j;
                }//while
                for( len=data[0].num;len<=sum;len++)
                {
                        if(sum%len!=0) continue;
                        total=sum/len;
                        if(dfs(0,0,0))
                        {
                                cout<<len<<endl;
                                break;
                        }
                }//for
                
                
        }//while
        
        return 0;
}