bzoj1036: [ZJOI2008]树的统计Count link-cut-tree版

题目传送门

这 算是link-cut-tree裸题啊 不过以前好像没有写过单点修改..............

#include<cstdio>
#include<cstring>
#include<algorithm>
#define LL long long
using namespace std;
const int M=;
int read(){
    int ans=,f=,c=getchar();
    while(c<''||c>''){if(c=='-') f=-; c=getchar();}
    while(c>=''&&c<=''){ans=ans*+(c-''); c=getchar();}
    return ans*f;
}
int n,m,c[M][],fa[M],a[M],b[M];
LL v[M],sum[M],mx[M];
bool rev[M];
bool isrt(int x){return c[fa[x]][]!=x&&c[fa[x]][]!=x;}
void up(int x){
    if(!x) return ;
    mx[x]=v[x]; sum[x]=v[x];
    int l=c[x][],r=c[x][];
    if(l) mx[x]=max(mx[x],mx[l]),sum[x]+=sum[l];
    if(r) mx[x]=max(mx[x],mx[r]),sum[x]+=sum[r];
}
void down(int x){
    if(!rev[x]) return ;
    rev[x]=;
    int l=c[x][],r=c[x][];
    if(l) swap(c[l][],c[l][]),rev[l]^=;
    if(r) swap(c[r][],c[r][]),rev[r]^=;
}
void rotate(int x){
    int y=fa[x],z=fa[y],l=,r=;
    if(c[y][]==x) l=,r=;
    if(!isrt(y)) c[z][c[z][]==y]=x;
    fa[y]=x; fa[x]=z; fa[c[x][r]]=y;
    c[y][l]=c[x][r]; c[x][r]=y;
    up(y); up(x);
}
int st[M],top=,S;
void splay(int x){
    st[++top]=x; for(int i=x;!isrt(i);i=fa[i]) st[++top]=fa[i];
    while(top) down(st[top--]);
    while(!isrt(x)){
        int y=fa[x],z=fa[y];
        if(!isrt(y)){
            if(c[z][]==y^c[y][]==x) rotate(x);
            else rotate(y);
        }
        rotate(x);
    }
}
void acs(int x0){
    for(int x=x0,y=;x;splay(x),c[x][]=y,up(x),y=x,x=fa[x]);
    splay(x0);
}
void mrt(int x){acs(x); swap(c[x][],c[x][]); rev[x]^=;}
void link(int x,int y){mrt(x); fa[x]=y;}
void spl(int x,int y){mrt(x); acs(y);}
int main()
{
    int x,y;
    n=read();
    for(int i=;i<n;i++) a[i]=read(),b[i]=read();
    for(int i=;i<=n;i++) v[i]=read();
    for(int i=;i<n;i++) link(a[i],b[i]);
    m=read();
    char ch[];
    for(int i=;i<=m;i++){
        scanf("%s",ch); x=read(); y=read();
        if(ch[]=='H') acs(x),v[x]=y;
        if(ch[]=='S') spl(x,y),printf("%lld\n",sum[y]);
        if(ch[]=='M') spl(x,y),printf("%lld\n",mx[y]);
    }
    return ;
}