解题：BOI 2008 Elect

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<algorithm>
 4 using namespace std;
 5 const int N=305,M=100005;
 6 int n,sum,ans,half;
 7 int a[N],dp[M];
 8 bool cmp(int a,int b)
 9 {
10     return a>b;
11 }
12 int main ()
13 {
14     scanf("%d",&n);
15     for(int i=1;i<=n;i++)
16         scanf("%d",&a[i]),sum+=a[i];
17     half=sum/2,sort(a+1,a+1+n,cmp);
18     for(int i=1;i<=n;i++)
19         for(int j=sum;~j;j--)
20         {
21             if(j>=a[i]) dp[j]=max(dp[j],dp[j-a[i]]+a[i]);
22             if(dp[j]>half&&dp[j]-a[i]<=half) ans=max(ans,dp[j]);
23         }
24     printf("%d",ans);
25     return 0;
26 }