hdu4010 Query on The Trees（lct）

1.连边x,y
2.以x为根，删边y,fa[y]
3.路径加法
4.路径最大值。

#include
#include
#include
#include
#define INF 2000000000
using namespace std;
int const N=300005;
int n,m,num=0,top=0,q[N],h[N];
int mx[N],v[N],tag[N],fa[N],c[N][2];
bool rev[N];
inline int read(){
    int x=0;char ch=getchar();
    while(ch<'0'||ch>'9') ch=getchar();
    while(ch>='0'&&ch<='9') x=x*10+ch-'0',ch=getchar();
    return x;
}
struct egde{
    int to,next;
}data[N<<1];
inline bool isroot(int x){
    return c[fa[x]][1]!=x&&c[fa[x]][0]!=x;
}
inline void update(int x){
    int l=c[x][0],r=c[x][1];
    mx[x]=max(max(mx[l],mx[r]),v[x]);
}
inline void pushdown(int x){
    int l=c[x][0],r=c[x][1];
    if(rev[x]){
        rev[x]^=1;rev[l]^=1;rev[r]^=1;
        swap(c[x][0],c[x][1]);
    }
    if(tag[x]){
        if(l) tag[l]+=tag[x],mx[l]+=tag[x],v[l]+=tag[x];
        if(r) tag[r]+=tag[x],mx[r]+=tag[x],v[r]+=tag[x];
        tag[x]=0;
    }
}
void rotate(int x){
    int y=fa[x],z=fa[y],l=x==c[y][1],r=l^1;
    if(!isroot(y)) c[z][y==c[z][1]]=x;
    fa[c[x][r]]=y;fa[y]=x;fa[x]=z;
    c[y][l]=c[x][r];c[x][r]=y;update(y);update(x);
}
void splay(int x){
    top=0;q[++top]=x;
    for(int i=x;!isroot(i);i=fa[i]) q[++top]=fa[i];
    while(top) pushdown(q[top--]);
    while(!isroot(x)){
        int y=fa[x],z=fa[y];
        if(!isroot(y)){
            if(c[y][1]==x^c[z][1]==y) rotate(x);
            else rotate(y);
        }rotate(x);
    }
}
void access(int x){
    int y=0;
    while(x){
        splay(x);c[x][1]=y;update(x);y=x;x=fa[x];
    }
}
int find(int x){
    access(x);splay(x);while(c[x][0]) x=c[x][0];return x;
}
void makeroot(int x){
    access(x);splay(x);rev[x]^=1;
}
void add(int w,int x,int y){
    makeroot(x);access(y);splay(y);
    tag[y]+=w;mx[y]+=w;v[y]+=w;
}
void link(int x,int y){
    makeroot(x);fa[x]=y;
}
void cut(int x,int y){
    makeroot(x);access(y);splay(y);
    c[y][0]=fa[c[y][0]]=0;update(y);
}
void query(int x,int y){
    makeroot(x);access(y);splay(y);
    printf("%d\n",mx[y]);
}
int main(){
//  freopen("hdu4010.in","r",stdin);
    while(scanf("%d",&n)!=EOF){ 
        for(int i=0;i<=n;i++) 
        tag[i]=rev[i]=fa[i]=c[i][0]=c[i][1]=h[i]=0;
        mx[0]=-INF;num=0;top=0;
        for(int i=1;iint x=read(),y=read();
            data[++num].to=y;data[num].next=h[x];h[x]=num;
            data[++num].to=x;data[num].next=h[y];h[y]=num;
        }q[++top]=1;fa[1]=-1;
        for(int k=1;k<=top;++k){
            int now=q[k];
            for(int i=h[now];i;i=data[i].next){
                int y=data[i].to;
                if(!fa[y]) fa[y]=now,q[++top]=y;
            }
        }fa[1]=0;
        for(int i=1;i<=n;++i) mx[i]=v[i]=read();m=read();
        while(m--){
            int op=read(),x,y,w;
            if(op==3){
                w=read();x=read();y=read();
                if(find(x)!=find(y)) puts("-1");
                else add(w,x,y);
            }
            else{
                x=read();y=read();
                if(op==1){
                    if(find(x)==find(y)) puts("-1");
                    else link(x,y);
                }if(op==2){
                    if(find(x)!=find(y)||x==y) puts("-1");
                    else cut(x,y);
                }if(op==4){
                    if(find(x)!=find(y)) puts("-1");
                    else query(x,y);
                }
            }
        }puts("");
    }
    return 0;
}