常州测试day2：flower

//2.flower#include<iostream>#include<cstdio>#include<queue>#include<map>#define fo(i,j,k) for(i=j;i<=k;i++)using namespace std;const int inf=-100000;int pre[200001],next[200001],a[200001];int ans;priority_queue < pair<int ,int > > q;int main(){    int n,m,i,j,k;    scanf("%d%d",&n,&m);    fo(i,1,n)    {        scanf("%d",&a[i]);        pre[i]=i-1,next[i]=i+1;        q.push(make_pair(a[i],i));    }    pre[1]=n;next[n]=1;    fo(i,1,m)    {        while(q.top().first!=a[q.top().second])          q.pop();        int x=q.top().second,l=pre[x],r=next[x];        ans+=a[x];        q.pop();        next[x]=next[r];        pre[next[r]]=x;        pre[x]=pre[l];        next[pre[l]]=x;        if(l && r) a[x]=max(inf,a[l]+a[r]-a[x]);        else a[x]=inf;        a[l]=a[r]=inf;        q.push(make_pair(a[x],x));    }    printf("%d\n",ans);    return 0;}