luogu 1484\1792 种树 奇怪的贪心可反悔

1484 种树 此版本是线性的，那么根据链表维护即可；

构建新点，点的左右分别是原整个区间的前驱及后继，再正常维护即可

注意两个版本的维护有所不同

第二个版本的维护直接将左右两点删除

1792 种树2  此版本是环

1484

#include<bits/stdc++.h>
#define ll long long 
using namespace std;
const int N=500010;
struct node{ll v;int id;bool operator <(node a)const{return v<a.v;}};
inline ll read(){ll x=0,f=1;char ch=getchar();while(!isdigit(ch)){if(ch=='-')f=-1;ch=getchar();}while(isdigit(ch)){x=(x<<1)+(x<<3)+(ch^48);ch=getchar();}return x*f;}
ll a[N],ans;
int l[N],r[N],vis[N];
priority_queue<node> q;
int n,k;
int main(){n=read();k=read();for(int i=1;i<=n;i++){a[i]=read();q.push((node){a[i],i});l[i]=i-1;r[i]=i+1;}int len=n;for(int i=1;i<=k;i++){while(!q.empty()&&vis[q.top().id]) q.pop();if(q.empty()||q.top().v<0)break;node u=q.top();q.pop();ans+=u.v;vis[u.id]=vis[l[u.id]]=vis[r[u.id]]=1;a[++len]=a[l[u.id]]+a[r[u.id]]-a[u.id];l[len]=l[l[u.id]],r[len]=r[r[u.id]];r[l[len]]=len;l[r[len]]=len;q.push((node){a[len],len});}printf("%lld\n",ans);return 0;
}

 

1792

#include<bits/stdc++.h>
#define M 200050
#define rep(i,x,y) for(register int i=x;i<=y;i++)
using namespace std;
inline int read(){int x=0,f=1;char ch=getchar();while(!isdigit(ch)){if(ch=='-')f=-1;ch=getchar();}while(isdigit(ch)){x=(x<<1)+(x<<3)+(ch^48);ch=getchar();}return x*f;}
struct node{int v,id;friend bool operator < (node x,node y){return x.v < y.v;}
};priority_queue<node> q;
int n,m,ans,chose,r[M],l[M],a[M];
bool vis[M];
void change(int x){vis[x]=1;r[l[x]]=r[x];l[r[x]]=l[x];r[x]=0;l[x]=0;}
int main(){n=read(),m=read();rep(i,1,n) a[i]=read();if((n>>1)<m){printf("Error!\n");return 0;}rep(i,1,n-1) r[i]=i+1;r[n]=1;rep(i,2,n) l[i]=i-1;l[1]=n;rep(i,1,n) q.push((node){a[i],i});rep(i,1,m){while(vis[q.top().id]) q.pop() ;node u=q.top();q.pop();ans+=u.v;int ll=l[u.id],rr=r[u.id];a[u.id]=a[ll]+a[rr]-a[u.id];change(ll);change(rr);q.push((node){a[u.id],u.id});}printf("%d\n",ans);return 0;
}