BZOJ 1500, 维修数列

Problem

Mean

Analysis

Code

#include<cstdio>
const int N=500005;
int n,m,o,cnt,top,p,t,c,a
,f
,son
[2],val
,sz
,sum
,pre
,suf
,mx
={-1000},rec
;
bool rev
,tag
;
char op[15];
int max(int a,int b){return a>b?a:b;}
void swap(int &a,int &b){int t=a;a=b;b=t;}
void revl(int x){if(!x) return;swap(son[x][0],son[x][1]),swap(pre[x],suf[x]);rev[x]^=1;}
void same(int x,int v){if(!x) return;val[x]=v;sum[x]=sz[x]*v;mx[x]=pre[x]=suf[x]=max(v,sum[x]);tag[x]=1;}
void read(int &x){
char c;
bool p=0;
while((c=getchar())<'0' || c>'9') if(c=='-') p=1;
x=c-'0';
while((c=getchar())>='0' && c<='9') x=x*10+c-'0';
if(p) x=-x;
}
int New(int &x){
if(top) x=rec[top--];
else x=++cnt;
son[x][0]=son[x][1]=rev[x]=tag[x]=0;
return x;
}
void erase(int x){
if(!x) return;
rec[++top]=x;
erase(son[x][0]),erase(son[x][1]);
}
void up(int x){
int l=son[x][0],r=son[x][1];
sz[x]=sz[l]+sz[r]+1;
sum[x]=sum[l]+sum[r]+val[x];
pre[x]=max(pre[l],sum[l]+val[x]+max(0,pre[r]));
suf[x]=max(suf[r],sum[r]+val[x]+max(0,suf[l]));
mx[x]=max(max(0,suf[l])+val[x]+max(0,pre[r]),max(mx[l],mx[r]));
}
void pb(int x){
if(rev[x]){
revl(son[x][0]),revl(son[x][1]);
rev[x]=0;
}
if(tag[x]){
same(son[x][0],val[x]),same(son[x][1],val[x]);
tag[x]=0;
}
}
int kth(int k){
int x=o,tmp;
while(1){
pb(x);
tmp=sz[son[x][0]]+1;
if(k==tmp) return x;
if(k<tmp) x=son[x][0];
else k-=tmp,x=son[x][1];
}
}
int build(int l,int r,int fa){
int mid=l+r>>1,x;
f[New(x)]=fa,val[x]=a[mid];
if(l<mid) son[x][0]=build(l,mid-1,x);
if(r>mid) son[x][1]=build(mid+1,r,x);
up(x);
return x;
}
void rotate(int x){
int y=f[x],w=son[y][1]==x;
son[y][w]=son[x][w^1];
if(son[x][w^1]) f[son[x][w^1]]=y;
if(f[y]) son[f[y]][son[f[y]][1]==y]=x;
f[x]=f[y];son[x][w^1]=y;f[y]=x;
up(y);
}
void splay(int x,int w){
int s=1,i=x,y;
a[1]=i;
while(f[i]) a[++s]=i=f[i];
while(s) pb(a[s--]);
while(f[x]!=w){
y=f[x];
if(f[y]!=w){
if((son[f[y]][0]==y)^(son[y][0]==x)) rotate(x);
else rotate(y);
}
rotate(x);
}
if(!w) o=x;
up(x);
}
int main(){
read(n),read(m);
for(int i=1;i<=n;i++) read(a[i]);
o=build(0,n+1,0);
while(m--){
scanf("%s",op);
if(op[2]=='S'){
read(p),read(t);
int x=kth(p+1),y=kth(p+2);
splay(x,0),splay(y,x);
for(int i=0;i<t;i++) read(a[i]);
son[y][0]=build(0,t-1,y);
up(y),up(x);
}else if(op[2]=='L'){
read(p),read(t);
int x=kth(p),y=kth(p+t+1);
splay(x,0),splay(y,x);
erase(son[y][0]);
son[y][0]=0;
up(y),up(x);
}else if(op[2]=='K'){
read(p),read(t),read(c);
int x=kth(p),y=kth(p+t+1);
splay(x,0),splay(y,x);
same(son[y][0],c);
up(y),up(x);
}else if(op[2]=='V'){
read(p),read(t);
int x=kth(p),y=kth(p+t+1);
splay(x,0),splay(y,x);
revl(son[y][0]);
up(y),up(x);
}else if(op[2]=='T'){
read(p),read(t);
int x=kth(p),y=kth(p+t+1);
splay(x,0),splay(y,x);
printf("%d\n",sum[son[y][0]]);
}else{
int x=kth(1),y=kth(sz[o]);
splay(x,0),splay(y,x);
printf("%d\n",mx[son[y][0]]);
}
}
return 0;
}