sgu 203

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构造哈夫曼树，开始乱搞，蛤蛤。

时间复杂度：O(n∗log2n)

事实上正解应该是 O(n)，蛤蛤。

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#include<cstdio>#include<cstdlib>#include<cstring>#include<iostream>#include<algorithm>#include<queue>const int MAXN = 500005;typedef std::priority_queue<long long,std::vector<long long>,std::greater<long long> >  Heap_ll;int n, p[MAXN];Heap_ll heap;long long ans;int main(){#ifndef ONLINE_JUDGE        freopen("sgu203.in","r",stdin);    freopen("sgu203.out","w",stdout);#endif    scanf("%d",&n);    for(int i = 1; i <= n; i++)        scanf("%d",&p[i]), heap.push(p[i]);    for(int i = 1; i < n; i++)    {        long long a, b;        a = heap.top(), heap.pop();        b = heap.top(), heap.pop();        heap.push(a + b), ans += a + b;    }    printf("%I64d\n",ans);  #ifndef ONLINE_JUDGE    fclose(stdin);    fclose(stdout);#endif    return 0;       }