bzoj1500

题解：

裸的splay

只要模板打的对。。。

代码：

#include<bits/stdc++.h>
using namespace std;
const int N=1000005;
const int inf=1e9;
int c[N][2],fa[N],a[N],key[N],sum[N],la[N],ra[N],ma[N],cov[N],size[N];
int x,y,l,r,z,ans,q[N],rev[N],n,m,tot,num,rot,st,ed,tail;
void update(int x)
{
    if (!x)return;
    la[x]=max(la[c[x][0]],sum[c[x][0]]+key[x]+max(0,la[c[x][1]]));
    ra[x]=max(ra[c[x][1]],sum[c[x][1]]+key[x]+max(0,ra[c[x][0]]));
    ma[x]=max(max(ma[c[x][0]],ma[c[x][1]]),key[x]+max(0,ra[c[x][0]])+max(0,la[c[x][1]]));
    sum[x]=sum[c[x][0]]+sum[c[x][1]]+key[x];
    size[x]=size[c[x][0]]+size[c[x][1]]+1;
}
void reverse(int x)
{
    if (!x)return;
    swap(c[x][0],c[x][1]);
    swap(la[x],ra[x]);
    rev[x]^=1;
}
void recover(int x,int z)
{
    if (!x)return;
    key[x]=cov[x]=z;
    sum[x]=size[x]*z;
    la[x]=ra[x]=ma[x]=max(z,sum[x]);
}
void down(int x)
{
    if (!x)return;
    if (rev[x])
     {
         reverse(c[x][0]);
         reverse(c[x][1]);
         rev[x]=0;
     }
    if (cov[x]!=-1e9)
     {
         recover(c[x][0],cov[x]);
         recover(c[x][1],cov[x]);
         cov[x]=-1e9;
     } 
}
void relax(int x,int rot)
{
    if (x!=rot)relax(fa[x],rot);
    down(x);
}
void rotate(int x,int &rot)
{
    int y=fa[x],z=fa[y];
    int p=(c[y][1]==x),q=p^1;
    if (y==rot)rot=x;
    else if (c[z][0]==y)c[z][0]=x;else c[z][1]=x;
    fa[x]=z;fa[y]=x;fa[c[x][q]]=y;
    c[y][p]=c[x][q];c[x][q]=y;
    update(y);
}
void splay(int x,int &rot)
{
    relax(x,tot);
    while (x!=rot)
     {
         int y=fa[x],z=fa[y];
         if (y!=rot)
          if ((c[y][0]==x)xor(c[z][0]==y))rotate(x,rot);
          else rotate(y,rot);
         rotate(x,rot); 
     }
    update(x); 
}
int pick()
{
    if (tail)return q[tail--];
    return ++num;
}
int setup(int x)
{
    int t=pick();
    key[t]=a[x];
    cov[t]=-1e9;
    rev[t]=0;
    la[t]=ra[t]=ma[t]=-1e9;
    return t;
}
int build(int l,int r)
{
    int mid=(l+r)/2,left=0,right=0;
    if (l<mid)left=build(l,mid-1);
    int t=setup(mid);
    if (r>mid)right=build(mid+1,r);
    if (left)c[t][0]=left,fa[left]=t;
    if (right)c[t][1]=right,fa[right]=t;
    update(t);
    return t;
}
int find(int t,int k)
{
    down(t);
    if (k==size[c[t][0]]+1)return t;
    if (k<size[c[t][0]]+1)return find(c[t][0],k);
    if (k>size[c[t][0]]+1)return find(c[t][1],k-size[c[t][0]]-1);
}
void del(int &x)
{
    if (!x)return;
    q[++tail]=x;
    fa[x]=0;
    del(c[x][0]);
    del(c[x][1]);
    la[x]=ra[x]=ma[x]=-1e9;
    x=0;
}
int main()
{
    scanf("%d%d",&n,&m);
    for (int i=2;i<=n+1;i++)scanf("%d",&a[i]);
    a[st=1]=0;a[ed=n+2]=0;
    ra[0]=la[0]=ma[0]=-1e9;
    rot=build(1,n+2);
    char sign[20];
    for (int i=1;i<=m;i++)
     {
         scanf("%s",&sign);
         if (sign[0]=='I')
          {
            scanf("%d %d",&x,&y);
            l=find(rot,x+1);r=find(rot,x+2);
            splay(r,rot);splay(l,c[rot][0]);
            for (int j=1;j<=y;j++)scanf("%d",&a[j]);
            int tmp=build(1,y);
            fa[tmp]=l;c[l][1]=tmp;                 
            update(l);update(r);
         } 
        if (sign[0]=='D')
         {
             scanf("%d%d",&x,&y);
             l=find(rot,x);r=find(rot,x+y+1);
             splay(r,rot);splay(l,c[rot][0]);
             del(c[l][1]);
             update(l);update(r);
         }
        if (sign[0]=='M'&&sign[2]=='K')
         {
             scanf("%d%d%d",&x,&y,&z);
             l=find(rot,x);r=find(rot,x+y+1);
             splay(r,rot);splay(l,c[rot][0]);
             recover(c[l][1],z);
          } 
        if (sign[0]=='R')
         {
             scanf("%d%d",&x,&y);
             l=find(rot,x);r=find(rot,x+y+1);
             splay(r,rot);splay(l,c[rot][0]);
             reverse(c[l][1]);
         } 
        if (sign[0]=='G')
         {
             scanf("%d%d",&x,&y);
             l=find(rot,x);r=find(rot,x+y+1);
             splay(r,rot);splay(l,c[rot][0]);
             ans=sum[c[l][1]];
             printf("%d
",ans);
         } 
        if (sign[0]=='M'&&sign[2]=='X')
         {
             splay(ed,rot);splay(st,c[rot][0]);
             ans=ma[c[st][1]];
             printf("%d
",ans);
         } 
     }
    return 0; 
}