题解 | 灵异背包？

#include <iostream>
#include <set>
using namespace std;
int a[100010],b[100010];
int n,l;
long long sum;
multiset<long long> tmp;

int main() {
    cin>>n;
    for(int i=0;i<n;i++){
        int x;cin>>x;
        if(x%2==0){a[i]=x;sum=sum+a[i];}
        else tmp.insert(x);
    }

   
for(auto it=tmp.begin();it!=tmp.end();it++){
   sum+=*it;}
   auto  it=tmp.begin();
   tmp.size()%2==0 ? cout<<sum:cout<<sum-*it ;
}