From 49a3293e003d9b4ed6989ebabfe20e9d512d351e Mon Sep 17 00:00:00 2001
From: Zengtudor <Zengtudor@outlook.com>
Date: Wed, 16 Jul 2025 10:15:54 +0800
Subject: [PATCH] done T633664

---
 src/7/16/T633664f.cpp | 88 ++++++++++++++++++++++++++++---------------
 1 file changed, 58 insertions(+), 30 deletions(-)

diff --git a/src/7/16/T633664f.cpp b/src/7/16/T633664f.cpp
index f454df8..e8e4087 100644
--- a/src/7/16/T633664f.cpp
+++ b/src/7/16/T633664f.cpp
@@ -1,49 +1,77 @@
+#include <algorithm>
 #include <cmath>
 #include <cstdint>
+#include <ios>
 #include <iostream>
-#include <istream>
-#include <unordered_set>
 #include <vector>
 
 using ll = int64_t;
 
-ll n;
-std::vector<ll> s;
-std::vector<ll> edg;
+// maxl = (n-1)*sum(s)
+ll n,maxl;
+std::vector<ll>s,lens;
+std::vector<std::vector<bool>> dpo;
+double ans{-1.0};
+
+void setMaxl(){
+    ll sums{};
+    for(ll i=1;i<=n;i++){
+        sums+=s[i];
+    }
+    maxl=(n-1)*sums;
+}
 
 double getArea(double a,double b,double c){
-    double s = a+b+c;
+    double s = (a+b+c)/2;
     return std::sqrt(s*(s-a)*(s-b)*(s-c));
 }
 
-void dfs(ll depth){
-    for(ll i=0;i<edg.size()-2+depth;i++){
-        ll sum{};
-        
-    }
-}
-
 int main(){
-    std::iostream::sync_with_stdio(false);
-    std::cin.tie(nullptr);
-    std::cout.tie(nullptr);
-
     std::cin>>n;
-    s.reserve(n+1);
-    edg.reserve(n*(n-1)/2+1);
-
-    for(ll i=0;i<n;i++){
-        ll tmp;
-        std::cin>>tmp;
-        s.emplace_back(tmp);
+    s.resize(n+1);
+    for(ll i=1;i<=n;i++){
+        std::cin>>s[i];
+    }
+    for(ll i=1;i<n;i++){
+        for(ll j=i+1;j<=n;j++){
+            lens.push_back(s[i]+s[j]);
+        }
+    }
+    setMaxl();
+    dpo.resize(maxl+1,std::vector<bool>(maxl+1,false));
+    dpo[0][0]=true;
+    for(ll k=0;k<(ll)lens.size();k++){
+        std::vector<std::vector<bool>> dpn(maxl+1,std::vector<bool>(maxl+1,false));
+        for(ll i=0;i<=maxl;i++){
+            for(ll j=0;j<=maxl;j++){
+                if(dpo[i][j]){
+                    if(i+lens[k]<=maxl){
+                        dpn[i+lens[k]][j]=true;
+                    }
+                    if(j+lens[k]<=maxl){
+                        dpn[i][j+lens[k]]=true;
+                    }
+                    dpn[i][j]=true;
+                }
+            }
+        }
+        dpo=dpn;
     }
 
-    for(ll i=0;i<s.size();i++){
-        for(ll j=0;j<s.size();j++){
-            if(i==j)continue;
-            edg.emplace_back(i+j);
+    for(ll i=0;i<=maxl;i++){
+        for(ll j=0;j<=maxl;j++){
+            if(dpo[i][j]){
+                ll c = maxl-i-j;
+                if(c<maxl/2.0){
+                    ans = std::max(ans,getArea(i, j, c));
+                }
+            }
         }
     }
 
-
-}
\ No newline at end of file
+    if(ans<0){
+        std::cout<<-1<<'\n';
+    }else{
+        std::cout<<ll(ans*10000)<<'\n';
+    }
+}   
\ No newline at end of file