JudgeOnline/upload/201806/1.pdf

#include<iostream>
#include<algorithm>
#include<cstdio>
#define LSON rt<<1
#define RSON rt<<1|1
#define DATA(x) b[x].data
#define SIGN(x) b[x].c
#define LSIDE(x) b[x].l
#define RSIDE(x) b[x].r
#define WIDTH(x) (RSIDE(x)-LSIDE(x)+1)
#define MAXN 300010
using namespace std;
int n,m,c=1,d=1,root=1;
int val[MAXN],head[MAXN],deep[MAXN],son[MAXN],size[MAXN],fa[MAXN],id[MAXN],pos[MAXN],top[MAXN];
struct Tree{int next,to;
}a[MAXN<<1];
struct Segment_Tree{long long data,c;int l,r;
}b[MAXN<<2];
inline int read(){int date=0,w=1;char c=0;while(c<'0'||c>'9'){if(c=='-')w=-1;c=getchar();}while(c>='0'&&c<='9'){date=date*10+c-'0';c=getchar();}return date*w;
}
inline void add(int x,int y){a[c].to=y;a[c].next=head[x];head[x]=c++;a[c].to=x;a[c].next=head[y];head[y]=c++;
}
void dfs1(int rt){son[rt]=0;size[rt]=1;for(int i=head[rt];i;i=a[i].next){int will=a[i].to;if(!deep[will]){deep[will]=deep[rt]+1;fa[will]=rt;dfs1(will);size[rt]+=size[will];if(size[son[rt]]<size[will])son[rt]=will;}}
}
void dfs2(int rt,int f){id[rt]=d++;pos[id[rt]]=rt;top[rt]=f;if(son[rt])dfs2(son[rt],f);for(int i=head[rt];i;i=a[i].next){int will=a[i].to;if(will!=fa[rt]&&will!=son[rt])dfs2(will,will);}
}
inline void pushup(int rt){DATA(rt)=DATA(LSON)+DATA(RSON);
}
inline void pushdown(int rt){if(!SIGN(rt)||LSIDE(rt)==RSIDE(rt))return;SIGN(LSON)+=SIGN(rt);DATA(LSON)+=SIGN(rt)*WIDTH(LSON);SIGN(RSON)+=SIGN(rt);DATA(RSON)+=SIGN(rt)*WIDTH(RSON);SIGN(rt)=0;
}
void buildtree(int l,int r,int rt){LSIDE(rt)=l;RSIDE(rt)=r;SIGN(rt)=0;if(l==r){DATA(rt)=val[pos[l]];return;}int mid=l+r>>1;buildtree(l,mid,LSON);buildtree(mid+1,r,RSON);pushup(rt);
}
void update(int l,int r,long long c,int rt){if(l<=LSIDE(rt)&&RSIDE(rt)<=r){SIGN(rt)+=c;DATA(rt)+=c*WIDTH(rt);return;}pushdown(rt);int mid=LSIDE(rt)+RSIDE(rt)>>1;if(l<=mid)update(l,r,c,LSON);if(mid<r)update(l,r,c,RSON);pushup(rt);
}
long long query(int l,int r,int rt){long long ans=0;if(l<=LSIDE(rt)&&RSIDE(rt)<=r)return DATA(rt);pushdown(rt);int mid=LSIDE(rt)+RSIDE(rt)>>1;if(l<=mid)ans+=query(l,r,LSON);if(mid<r)ans+=query(l,r,RSON);return ans;
}
int LCA(int x,int y){while(top[x]!=top[y]){if(deep[top[x]]<deep[top[y]])swap(x,y);x=fa[top[x]];}if(deep[x]>deep[y])swap(x,y);return x;
}
int check(int x){if(x==root)return -1;if(id[x]<=id[root]&&id[root]<=id[x]+size[x]-1){int y=root;while(deep[y]>deep[x]){if(fa[top[y]]==x)return top[y];y=fa[top[y]];}return son[x];}return 0;
}
void update_subtree(int x,int k){int y=check(x);if(y==-1)update(1,n,k,1);else if(y==0)update(id[x],id[x]+size[x]-1,k,1);else{update(1,n,k,1);update(id[y],id[y]+size[y]-1,-k,1);}
}
void query_subtree(int x){long long s;int y=check(x);if(y==-1)s=query(1,n,1);else if(y==0)s=query(id[x],id[x]+size[x]-1,1);else s=query(1,n,1)-query(id[y],id[y]+size[y]-1,1);printf("%lld\n",s);
}
void work(){int f,x,y,k;while(m--){f=read();x=read();if(f==1)root=x;else if(f==2){y=read();k=read();int lca=LCA(x,y),lca1=LCA(x,root),lca2=LCA(y,root);if(deep[lca1]>deep[lca])lca=lca1;if(deep[lca2]>deep[lca])lca=lca2;update_subtree(lca,k);}else query_subtree(x);}
}
void init(){int x,y;n=read();m=read();for(int i=1;i<=n;i++)val[i]=read();for(int i=1;i<n;i++){x=read();y=read();add(x,y);}deep[1]=1;dfs1(1);dfs2(1,1);buildtree(1,n,1);
}
int main(){init();work();return 0;
}