这么写耗时会不会很长？

**0. #include<cstdio>**
**0. #include<cstdlib>**
**0. #include<iostream>**
**0. #include<map>**
**0. #define FOR(i,j,k) for(int i=j;i<=k;i++)**
**0. using namespace std;**
**0. int num,ans;**
**0. map<int,int> g;**
**0. map<int,int>::iterator it,t;**
**0. void next()**
**0. {**
**0. for(it=g.begin();it!=g.end();it++)**
**0. {**
**0. if(it->second)return;**
**0. }**
**0. }**
**0. int main()**
**0. {**
**0. bool b=1;**
**0. cin>>num;**
**0. FOR(i,1,num)**
**0. {**
**0. int l;**
**0. cin>>l;**
**0. g[l]++;**
**0. }**
**0. for(t=g.begin();t!=g.end();t++)**
**0. {**
**0. while(t->second)**
**0. {**
**0. t->second--;**
**0. next();**
**0. if(it==g.end())**
**0. break;**
**0. it->second--;**
**0. ans+=t->first+it->first;**
**0. g[t->first+it->first]++;**
**0. }**
**0. }**
**0. cout<<ans;**
**0. return 0;**
**0. }**