*triangular <pku 1948>

 //  刚开始，没想到神马好思路，原来这些fence全部都要用到，= =！，果断做了...
Source Code

Problem: 1948  User: eth1 
Memory: 1372K  Time: 125MS 
Language: G++  Result: Accepted 

Source Code 
#include <iostream>
#include <algorithm>
#include <cstring>
#include <cmath>
using namespace std;
bool map[805][805];
int f[45];
bool check(int a,int b,int c)
{
    if(a+b>c && a+c>b && b+c>a) return 1;
    return 0;
}
int ans(int a,int b,int c)
{
    double tem = (a+b+c)*1.0/2;
    return (int)(sqrt(tem*(tem-a)*(tem-b)*(tem-c))*100);
}
int main()
{
    int t,sum=0;
    cin>>t;
    for(int i=0;i<t;i++) {cin>>f[i];sum+=f[i];}
    sort(f,f+t);
    memset(map,0,sizeof(map));
    map[0][0]=1;
    for(int i=0;i<t;i++)
    {
        for(int j=sum/2;j>=0;j--)
        {
            for(int k=sum/2;k>=0;k--)
            {
                if( j>=f[i] && map[j-f[i]][k] || (k>=f[i] && map[j][k-f[i]]) )
                map[j][k]=1;
            }
        }
    }
    int maxx=-1;
    for(int i=sum/2;i>0;i--)
    for(int j=sum/2;j>0;j--)
    {
        if(map[i][j])
        {
            int tem = sum-i-j;
            if(check(tem,i,j))
            {
                maxx = max(maxx,ans(tem,i,j));
            }
        }
    }
    cout<<maxx<<endl;
    return 0;
}