【fhq Treap】bzoj1500（听说此题多码上几遍就能牢记fhq Treap）

//by 减维
#include<cstdio>
#include<iostream>
#include<cstring>
#include<queue>
#include<cstdlib>
#include<ctime>
#include<cmath>
#include<map>
#include<bitset>
#include<algorithm>
#define inf 1<<30
#define ll long long
using namespace std;
 
int n,m,rt,sz,siz[500005],son[500005][2],val[500005],lm[500005],rm[500005],ma[500005],sum[500005],mark[500005],cov[500005],pri[500005];
int a[200005];
char ch[25];
queue<int>q;
 
int newnode(int v)
{
    int x;
    if(!q.empty())
        x=q.front(),q.pop();
    else x=++sz;
    siz[x]=1;
    son[x][0]=son[x][1]=mark[x]=0;
    cov[x]=inf;pri[x]=rand();
    val[x]=sum[x]=ma[x]=v;
    lm[x]=rm[x]=max(0,v);
    return x;
}
 
void upda(int x)
{
    if(son[x][0]&&son[x][1]){
        siz[x]=siz[son[x][0]]+siz[son[x][1]]+1;
        sum[x]=sum[son[x][0]]+sum[son[x][1]]+val[x];
        ma[x]=max(max(ma[son[x][0]],ma[son[x][1]]),rm[son[x][0]]+lm[son[x][1]]+val[x]);
        lm[x]=max(lm[son[x][0]],sum[son[x][0]]+val[x]+lm[son[x][1]]);
        rm[x]=max(rm[son[x][1]],sum[son[x][1]]+val[x]+rm[son[x][0]]);
    }else if(son[x][0]){
        siz[x]=siz[son[x][0]]+1;
        sum[x]=sum[son[x][0]]+val[x];
        ma[x]=max(ma[son[x][0]],rm[son[x][0]]+val[x]);
        lm[x]=max(lm[son[x][0]],sum[son[x][0]]+val[x]);
        lm[x]=max(0,lm[x]);
        rm[x]=max(0,rm[son[x][0]]+val[x]);
    }else if(son[x][1]){
        siz[x]=siz[son[x][1]]+1;
        sum[x]=sum[son[x][1]]+val[x];
        ma[x]=max(ma[son[x][1]],lm[son[x][1]]+val[x]);
        rm[x]=max(rm[son[x][1]],sum[son[x][1]]+val[x]);
        rm[x]=max(0,rm[x]);
        lm[x]=max(0,lm[son[x][1]]+val[x]);
    }else{
        siz[x]=1;sum[x]=ma[x]=val[x];
        lm[x]=rm[x]=max(0,val[x]);
    }
}
 
void covered(int x,int v)
{
    val[x]=v;
    sum[x]=siz[x]*v;
    lm[x]=rm[x]=max(0,sum[x]);
    ma[x]=max(sum[x],val[x]);
    cov[x]=v;
}
 
void zhuan(int now)
{
    swap(son[now][0],son[now][1]);
    swap(lm[now],rm[now]);
    mark[now]^=1;
}
 
void pd(int now)
{
    if(mark[now]){
        if(son[now][0])zhuan(son[now][0]);
        if(son[now][1])zhuan(son[now][1]);
    }
    if(cov[now]!=inf){
        if(son[now][0])covered(son[now][0],cov[now]);
        if(son[now][1])covered(son[now][1],cov[now]);
    }
    mark[now]=0;cov[now]=inf;
}
 
int build(int l,int r)
{
    if(l>r)return 0;
    int mid=(l+r)>>1,v=a[mid];
    int now=newnode(v);
    son[now][0]=build(l,mid-1);
    son[now][1]=build(mid+1,r);
    upda(now);
    return now;
}
 
void dfs(int now)
{
    if(!now)return;
    dfs(son[now][0]);
    printf("%d ",val[now]);
    dfs(son[now][1]);
}
 
void spli(int now,int k,int &x,int &y)
{
    if(!now)x=y=0;
    else{
        pd(now);
        if(k<=siz[son[now][0]])
            y=now,spli(son[now][0],k,x,son[now][0]);
        else
            x=now,spli(son[now][1],k-siz[son[now][0]]-1,son[now][1],y);
        upda(now);
    }
}
 
int merge(int x,int y)
{
    if(!x||!y)return x+y;
    pd(x),pd(y);
    if(pri[x]<pri[y])
    {
        son[x][1]=merge(son[x][1],y);
        upda(x);
        return x;
    }else{
        son[y][0]=merge(x,son[y][0]);
        upda(y);
        return y;
    }
}
 
void rudui(int x)
{
    if(!x)return ;
    q.push(x);
    rudui(son[x][0]);
    rudui(son[x][1]);
}
 
int main()
{
    scanf("%d%d",&n,&m);
    for(int i=1;i<=n;++i)scanf("%d",&a[i]);
    rt=build(1,n);
    int pos,num,x,y,z,k,b,c,d;
    for(int i=1;i<=m;++i)
    {
        //dfs(rt);printf("\n"); 
        scanf("%s",ch+1);
        if (ch[1]==‘I‘){
            scanf("%d %d",&pos,&num);
            for(int i=1;i<=num;++i)scanf("%d",&a[i]);
            z=build(1,num);
            spli(rt,pos,x,y);
            rt=merge(merge(x,z),y);
        }else if (ch[1]==‘D‘){
            scanf("%d%d",&pos,&num);
            spli(rt,pos-1,x,y);
            spli(y,num,b,c);
            rt=merge(x,c);
            rudui(b);
        }else if (ch[1]==‘M‘ && ch[3] ==‘K‘){
            scanf("%d%d%d",&pos,&num,&k);
            spli(rt,pos-1,x,y);
            spli(y,num,b,c);
            covered(b,k);
            rt=merge(x,merge(b,c));
        }else if (ch[1]==‘R‘){
            scanf("%d%d",&pos,&num);
            spli(rt,pos-1,x,y);
            spli(y,num,b,c);
            zhuan(b);
            rt=merge(x,merge(b,c));
        }else if (ch[1]==‘G‘){
            scanf("%d%d",&pos,&num);
            spli(rt,pos-1,x,y);
            spli(y,num,b,c);
            printf("%d\n",sum[b]);
            rt=merge(x,merge(b,c));
        }else{
            printf("%d\n",ma[rt]);
        }
    }
    return 0;
}