bzoj1500: [NOI2005]维修数列 splay

/**************************************************************
    Problem: 1500
    User: walfy
    Language: C++
    Result: Accepted
    Time:9792 ms
    Memory:26516 kb
****************************************************************/
 
//#pragma comment(linker, "/stack:200000000")
//#pragma GCC optimize("Ofast,no-stack-protector")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
//#pragma GCC optimize("unroll-loops")
#include<bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define pi acos(-1.0)
#define ll long long
#define vi vector<int>
#define mod 1000000007
#define ld long double
#define C 0.5772156649
#define ls l,m,rt<<1
#define rs m+1,r,rt<<1|1
#define pil pair<int,ll>
#define pli pair<ll,int>
#define pii pair<int,int>
#define cd complex<double>
#define ull unsigned long long
#define base 1000000000000000000
#define fio ios::sync_with_stdio(false);cin.tie(0)
 
using namespace std;
 
const double eps=1e-6;
const int N=200000+10,maxn=20000+10,inf=0x3f3f3f3f,INF=0x3f3f3f3f3f3f3f3f;
 
struct Splay{
    struct Node{
        Node* ch[2];
        int v,sum,ma,le,ri;
        int s,maxx;
        int flip,lazy;
        int cmp(int x)const{
            int d = x - ch[0]->s;
            if(d==1)return -1;
            return d<=0 ? 0:1;
        }
        void maintain()
        {
            s = 1 + ch[0]->s + ch[1]->s;
            maxx = max(max(ch[0]->maxx,ch[1]->maxx),v);
            sum = v + ch[0]->sum + ch[1]->sum;
            le = max(ch[0]->le,ch[0]->sum+v+ch[1]->le);
            if(ch[0]->le == ch[0]->sum)le = max(le, ch[0]->le + v + ch[1]->le);
            ri = max(ch[1]->ri,ch[1]->sum+v+ch[0]->ri);
            if(ch[1]->ri == ch[1]->sum)ri = max(ri, ch[0]->ri + v + ch[1]->ri);
            ma = max(max(ch[0]->ma,ch[1]->ma),ch[0]->ri+ch[1]->le+v);
        }
        void pushdown()
        {
            if(flip)
            {
                flip=0;
                swap(ch[0],ch[1]);
                swap(ch[0]->le,ch[0]->ri);
                swap(ch[1]->ri,ch[1]->le);
                ch[0]->flip = !(ch[0]->flip);
                ch[1]->flip = !(ch[1]->flip);
            }
            if(lazy!=inf)
            {
                if(ch[0]->s!=0)
                {
                    ch[0]->v=ch[0]->maxx=lazy;
                    ch[0]->sum=lazy*ch[0]->s;
                    ch[0]->ma=ch[0]->le=ch[0]->ri=max(0,ch[0]->sum);
                }
                if(ch[1]->s!=0)
                {
                    ch[1]->v=ch[1]->maxx=lazy;
                    ch[1]->sum=lazy*ch[1]->s;
                    ch[1]->ma=ch[1]->le=ch[1]->ri=max(0,ch[1]->sum);
                }
                ch[0]->lazy=ch[1]->lazy=lazy;
                lazy=inf;
            }
        }
    };
    Node* null;
    void Rotate(Node* &o,int d)
    {
        Node* k = o->ch[d^1];
        o->ch[d^1] = k->ch[d];
        k->ch[d] = o;
        o->maintain();k->maintain();
        o = k;
    }
    void splay(Node* &o,int k)
    {
        o->pushdown();
        int d = o->cmp(k);
        if(d==1)k -= o->ch[0]->s + 1;//利用二叉树性质
        if(d!=-1)
        {
            Node* p = o->ch[d];
            p->pushdown();
            int d2 = p->cmp(k);
            int k2 = (d2==0 ? k:k-p->ch[0]->s-1);
            if(d2!=-1)
            {
                splay(p->ch[d2],k2);
                if(d==d2)Rotate(o,d^1);
                else Rotate(o->ch[d],d);
            }
            Rotate(o,d^1);
        }
    }
    Node* Merge(Node* left,Node* right)
    {
        splay(left,left->s);//把排名最大的数splay到根
        left->ch[1] = right;
        left->maintain();
        return left;
    }
    void split(Node* o,int k,Node* &left,Node* &right)
    {
        splay(o,k);//把排名为k的节点splay到根，右侧子树所有节点排名比k大，左侧小
        right = o->ch[1];
        o->ch[1] = null;
        left = o;
        left->maintain();
    }
    Node *root,*left,*right;
    void init(int sz)
    {
        null=new Node;
        null->s=null->sum=null->le=null->ri=0;
        null->maxx=-inf;
        root=new Node;
        scanf("%d",&root->v);
        root->flip=0;root->lazy=inf;
        root->sum=root->maxx=root->v;
        root->ma=root->ri=root->le=max(0,root->v);
        root->ch[0]=root->ch[1]=null;
        root->maintain();
        Node* p;
        for(int i=2;i<=sz;i++)
        {
            p=new Node;
            scanf("%d",&p->v);
            p->s=p->flip=0;
            p->lazy=inf;
            p->sum=p->maxx=p->v;
            p->ma=p->le=p->ri=max(0,p->v);
            p->ch[0]=root,p->ch[1]=null;
            root=p;
            root->maintain();
        }
    }
    void ins(int pos,int x)
    {
        Node *mid;mid=new Node();
        mid->v=mid->sum=mid->maxx=x;
        mid->flip=0,mid->lazy=inf;
        mid->ma=mid->le=mid->ri=max(x,0);
        mid->ch[0]=mid->ch[1]=null;
        mid->maintain();
        if(pos==0)root=Merge(mid,root);
        else if(pos==root->s)root=Merge(root,mid);
        else
        {
            split(root,pos,left,right);
            root=Merge(left,Merge(mid,right));
//            print(root);
        }
    }
    void del(int l,int r)
    {
        if(l==1&&r==root->s)dele(root),root=null;
        else if(l==1&&r!=root->s)
        {
            split(root,r,left,right);
            root=right;dele(left);
        }
        else if(l!=1&&r==root->s)
        {
            split(root,l-1,left,right);
            root=left;dele(right);
        }
        else
        {
            split(root,r,left,right);
            Node *mid;
            split(left,l-1,left,mid);
            root=Merge(left,right);
            dele(mid);
        }
    }
    void dele(Node *&o)
    {
        if(o->ch[0]!=null)dele(o->ch[0]);
        if(o->ch[1]!=null)dele(o->ch[1]);
        delete(o);
    }
    int change(int l,int r,int x,int op)
    {
        int ans=0;
        if(l==1&&r==root->s)
        {
            if(op==1)
            {
                root->lazy=root->v=root->maxx=x;
                root->sum=root->s*x;
                if(x>0)root->ma=root->le=root->ri=root->sum;
                else root->ma=root->le=root->ri=0;
            }
            else if(op==2)
            {
                swap(root->le,root->ri);
                root->flip^=1;
            }
            else ans=root->sum;
        }
        else if(l==1&&r!=root->s)
        {
            split(root,r,left,right);
            if(op==1)
            {
                left->lazy=left->v=left->maxx=x;
                left->sum=left->s*x;
                if(x>0)left->ma=left->le=left->ri=left->sum;
                else left->ma=left->le=left->ri=0;
            }
            else if(op==2)
            {
                swap(left->le,left->ri);
                left->flip^=1;
            }
            else ans=left->sum;
            root=Merge(left,right);
        }
        else if(l!=1&&r==root->s)
        {
            split(root,l-1,left,right);
            if(op==1)
            {
                right->lazy=right->v=right->maxx=x;
                right->sum=right->s*x;
                if(x>0)right->ma=right->le=right->ri=right->sum;
                else right->ma=right->le=right->ri=0;
            }
            else if(op==2)
            {
                swap(right->le,right->ri);
                right->flip^=1;
            }
            else ans=right->sum;
            root=Merge(left,right);
        }
        else
        {
            split(root,r,left,right);
            Node *mid;
            split(left,l-1,left,mid);
            if(op==1)
            {
                mid->lazy=mid->v=mid->maxx=x;
                mid->sum=mid->s*x;
                if(x>0)mid->ma=mid->le=mid->ri=mid->sum;
                else mid->ma=mid->le=mid->ri=0;
            }
            else if(op==2)
            {
                swap(mid->le,mid->ri);
                mid->flip^=1;
            }
            else ans=mid->sum;
            root=Merge(left,Merge(mid,right));
        }
        return ans;
    }
    void print(Node *o)
    {
        o->pushdown();
        printf("%d %d %d %d %d %d
",o->ch[0]->v,o->v,o->ch[1]->v,o->ma,o->le,o->ri);
        if(o->ch[0]!=null)print(o->ch[0]);
        if(o->ch[1]!=null)print(o->ch[1]);
    }
}sp;
int main()
{
    int n,m;
    scanf("%d%d",&n,&m);
    sp.init(n);
//    sp.print(sp.root);
    while(m--)
    {
        char op[20];
        scanf("%s",op);
        if(op[0]=='I')
        {
            int pos,x,y;
            scanf("%d%d",&pos,&x);
            for(int i=0;i<x;i++)
            {
                scanf("%d",&y);
                sp.ins(pos+i,y);
            }
        }
        else if(op[0]=='D')
        {
            int pos,x;
            scanf("%d%d",&pos,&x);
            sp.del(pos,pos+x-1);
        }
        else if(op[0]=='M'&&op[2]=='K')
        {
            int pos,x,c;
            scanf("%d%d%d",&pos,&x,&c);
            sp.change(pos,pos+x-1,c,1);
        }
        else if(op[0]=='R')
        {
            int pos,x;
            scanf("%d%d",&pos,&x);
            sp.change(pos,pos+x-1,0,2);
        }
        else if(op[0]=='G')
        {
            int pos,x;
            scanf("%d%d",&pos,&x);
            printf("%d
",x>0?sp.change(pos,pos+x-1,0,3):0);
        }
        else printf("%d
",sp.root->maxx<0?sp.root->maxx:sp.root->ma);
    }
//    puts("-----------");
//    sp.print(sp.root);
    return 0;
}
/********************
9 5
2 -6 3 5 1 -5 -3 6 3
GET-SUM 5 4
MAX-SUM
INSERT 8 3 -5 7 2
DELETE 12 1
MAX-SUM
********************/