luoguP1120 小木棍 ［数据加强版］ 

  1 #include<bits/stdc++.h>
  2 using namespace std;
  3 const int maxn=1e6+5;
  4 int n,ans,tot,maxx,mark;
  5 int sum,num,len;
  6 int a[maxn];
  7 bool v[maxn];
  8 template <class t>void red(t &x)
  9 {
 10     x=0;
 11     int w=1;
 12     char ch=getchar();
 13     while(ch<'0'||ch>'9')
 14     {
 15         if(ch=='-')
 16             w=-1;
 17         ch=getchar();
 18     }
 19     while(ch>='0'&&ch<='9')
 20     {
 21         x=(x<<3)+(x<<1)+ch-'0';
 22         ch=getchar();
 23     }
 24     x*=w;
 25 }
 26 void input()
 27 {
 28     freopen("input.txt","r",stdin);
 29     //freopen("output.txt","w",stdout);
 30 }
 31 bool cmp(int x,int y)
 32 {
 33     return x>y;
 34 }
 35 void dfs(int cur,int k,int cnt)
 36 {
 37     //printf("%d %d %d\n",a[cur-1],k,cnt);
 38     if(cnt==num)
 39     {
 40         ans=len;
 41         mark=1;
 42         return;
 43     }
 44     if(!k)
 45     {    
 46         
 47         int i;
 48         for(i=1;i<=tot;++i)
 49             if(!v[i])
 50             {
 51                 v[i]=1;
 52                 break;
 53             }
 54         //printf("%d\n",cnt+1);
 55         dfs(i+1,len-a[i],cnt+1);
 56         if(mark)
 57             return;
 58         v[i]=0;
 59     }        
 60     for(int i=cur;i<=tot;++i)
 61         if(!v[i]&&k>=a[i])
 62         {
 63             v[i]=1;
 64             dfs(i+1,k-a[i],cnt);
 65             v[i]=0;
 66             if(k==a[i])
 67                 return;
 68             int j=i+1;
 69             while(i<tot&&a[j]==a[i])
 70                 i++;
 71             if(i==n)
 72                 return;
 73             if(mark)
 74                 return;
 75         }            
 76 }
 77 int main()
 78 {
 79     //input();
 80     red(n);
 81     int x;
 82     for(int i=1;i<=n;++i)
 83     {
 84         red(x);
 85         if(x<=50)
 86         {
 87             a[++tot]=x;
 88             maxx=max(maxx,x);
 89             sum+=x;
 90         }
 91     }
 92     ans=sum;
 93     sort(a+1,a+tot+1,cmp);
 94     for(int i=maxx;i<=sum/2;++i)
 95     {
 96         if(sum%i)
 97             continue;        
 98         //printf("\n%d\n",i);
 99         num=sum/i;
100         len=i;
101         mark=0;
102         memset(v,0,sizeof(v));
103         v[1]=1;
104         dfs(1,len-a[1],1);
105         if(mark)
106             break;
107     }
108     printf("%d",ans);
109     return 0;
110 }
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posted @ 2019-06-12 12:58  Achen_sy  阅读(132)  评论(0)    收藏  举报