妹子刚学OI，求助记忆化搜索QAQ

#include<bits/stdc++.h>
using namespace std;
int n;
int a[80];
double c,p;
int maxx;
int f[80][80][80][80];
int s(double x,double y,double z){
    if(x+y<z || x+z<y || y+z<x) return 0;
    return sqrt(p*(p-x)*(p-y)*(p-z))*100;
}
int dfs(int dep,int x,int y,int z){
    if(f[dep][x][y][z]) return f[dep][x][y][z];
    if(dep>n){
        return max(maxx,s(x,y,z));
    }
    if(x>p || y>p || z>p) return 0;
    return f[dep][x][y][z]=max(dfs(dep+1,x+a[dep],y,z),max(dfs(dep+1,x,y+a[dep],z),dfs(dep+1,x,y,z+a[dep])));
}
int main(){
    //freopen("data.txt","r",stdin);
    //freopen("my.txt","w",stdout);
    cin>>n;
    for(int i=1;i<=n;i++){
        scanf("%d",&a[i]);
        c+=a[i];
    }
    p=c/2;
    sort(a+1,a+n+1);
    if(a[n]>=p){
        cout<<-1;
        return 0;
    }
    cout<<dfs(1,0,0,0)<<endl;
    return 0;
}

29
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33
24
31
30
10
14
29
34
10
21
12
12
15
24
6
32
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38
3
17
4
34
22
4
4
1
15
34