poj 1011 搜索（剪枝）

#include<cstdio>#include<cstring>#include<algorithm>#define MIN(x,y) ((x)>(y)?(y):(x))using namespace std;int d[70],m[70],total,flag,vis[70],n,t;int dfs(int begin,int aim,int rest){if(rest==0&&aim==0)return 1;    if(aim==0){if(dfs(0,t,rest))return 1;elsereturn 0;} for(int i=begin;i<n;i++){if(vis[i])continue;if(d[i]>aim)continue;vis[i]=1;if(dfs(i+1,aim-d[i],rest-1))return 1;vis[i]=0;if(aim==t||aim==d[i])break;}return 0;}bool cmp(int a,int b){return a>b;}int main(){while(~scanf("%d",&n)&&n){int x,sum;memset(d,0,sizeof(d));memset(vis,0,sizeof(vis)); total=0x3f3f3f3f; sum=0;for(int i=0;i<n;i++){     scanf("%d",&d[i]);     sum+=d[i];     total=MIN(total,d[i]);    }    sort(d,d+n,cmp);     for(t=total;t<=sum;t++){if(sum%t)continue;memset(vis,0,sizeof(vis));    if(dfs(0,t,n))    {    printf("%d\n",t);    break;}}}}