bzoj1724[Usaco2006 Nov]Fence Repair 切割木板

小根堆维护一下就好了。

#include 
#include 
#include
#define fo(i,a,b) for(int i=a;i<=b;i++)
using namespace std;
int heap[100001],sz=0;
typedef long long ll;
int n;
inline void put(int y)
{
    heap[++sz]=y;
    int x=sz;
    while (x>1&&heap[x>>1]>heap[x])
    {
        swap(heap[x],heap[x>>1]);
        x>>=1;
    }
}
inline int get()
{
    int t=heap[1];
    heap[1]=heap[sz--];
    int x=1;
    while (x<=(sz>>1))
    {
        int next=x<<1;
        if (next1]if (heap[next]>=heap[x])return t;
        swap(heap[next],heap[x]);
        x=next;
    }
    return t;
}
int main()
{

    scanf("%d",&n);
    fo(i,1,n)
    {
        int x;
        scanf("%d",&x);
        put(x);
    }
    ll ans=0;
    fo(i,1,n-1)
    {
        int x=get(),y=get();
        put(x+y);
        ans+=x+y;
    }
    printf("%lld\n",ans);
    return 0;
}