3531: [Sdoi2014]旅行 (树链剖分+线段树)

#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdlib>
#include<cstdio>
#define inf 0x7fffffff
using namespace std;
inline int read(){
int x=0,f=1;char ch=getchar();
while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
return x*f;
}
const int maxn = 200001, maxm = 10000001;
struct edge{int to,next;}e[maxn];
int n,m,cnt,tot,sz,w[maxn],c[maxn],head[maxn],root[maxn],deep[maxn],son[maxn],pos[maxn],belong[maxn],fa[maxn][17],ls[maxm],rs[maxm],mx[maxm],sum[maxm];
inline void ins(int u,int v){
e[++cnt]=(edge){v,head[u]};head[u]=cnt;
e[++cnt]=(edge){u,head[v]};head[v]=cnt;
}
inline void dfs1(int x,int Fa){
son[x]=1;
for(int i=1;i<=16;i++){
if((1<<i)>deep[x])break;
fa[x][i]=fa[fa[x][i-1]][i-1];
}
for(int i=head[x];i;i=e[i].next){
if(e[i].to==Fa)continue;
fa[e[i].to][0]=x;
deep[e[i].to]=deep[x]+1;
dfs1(e[i].to,x);
son[x]+=son[e[i].to];
}
}
inline void dfs2(int x,int chain){
int k=0;
pos[x]=++tot;belong[x]=chain;
for(int i=head[x];i;i=e[i].next)
if(son[e[i].to]>son[k]&&deep[x]<deep[e[i].to])
k=e[i].to;
if(k)dfs2(k,chain);
for(int i=head[x];i;i=e[i].next)
if(deep[e[i].to]>deep[x]&&e[i].to!=k)
dfs2(e[i].to,e[i].to);
}
inline int lca(int x,int y){
if(deep[x]<deep[y])swap(x,y);
int d=deep[x]-deep[y];
for(int i=0;i<=16;i++)
if((1<<i)&d)x=fa[x][i];
for(int i=16;i>=0;i--)
if(fa[x][i]!=fa[y][i])
x=fa[x][i],y=fa[y][i];
if(x==y)return x;
else return fa[x][0];
}
inline void update(int k){
mx[k]=max(mx[ls[k]],mx[rs[k]]);
sum[k]=sum[ls[k]]+sum[rs[k]];
}
void change(int &k,int l,int r,int x,int num){
if(!k)k=++sz;
if(l==r){mx[k]=sum[k]=num;return;}
int mid=(l+r)>>1;
if(x<=mid)change(ls[k],l,mid,x,num);
else change(rs[k],mid+1,r,x,num);
update(k);
}
inline int askmx(int k,int l,int r,int x,int y){
if(!k)return 0;
if(l==x&&y==r)return mx[k];
int mid=(l+r)>>1;
if(y<=mid)return askmx(ls[k],l,mid,x,y);
else if(x>mid)return askmx(rs[k],mid+1,r,x,y);
else return max(askmx(ls[k],l,mid,x,mid),askmx(rs[k],mid+1,r,mid+1,y));
}
inline int asksum(int k,int l,int r,int x,int y){
if(!k)return 0;
if(l==x&&y==r)return sum[k];
int mid=(l+r)>>1;
if(y<=mid)return asksum(ls[k],l,mid,x,y);
else if(x>mid)return asksum(rs[k],mid+1,r,x,y);
else return asksum(ls[k],l,mid,x,mid)+asksum(rs[k],mid+1,r,mid+1,y);
}
inline int solvemx(int c,int x,int f){
int mx=0;
while(belong[x]!=belong[f]){
mx=max(mx,askmx(root[c],1,n,pos[belong[x]],pos[x]));
x=fa[belong[x]][0];
}
mx=max(mx,askmx(root[c],1,n,pos[f],pos[x]));
return mx;
}
inline int solvesum(int c,int x,int f){
int sum=0;
while(belong[x]!=belong[f]){
sum+=asksum(root[c],1,n,pos[belong[x]],pos[x]);
x=fa[belong[x]][0];
}
sum+=asksum(root[c],1,n,pos[f],pos[x]);
return sum;
}
int main(){
n=read();m=read();
for(int i=1;i<=n;i++)
w[i]=read(),c[i]=read();
for(int i=1;i<n;i++)
ins(read(),read());
dfs1(1,0);dfs2(1,1);
for(int i=1;i<=n;i++)
change(root[c[i]],1,n,pos[i],w[i]);
for(int i=1;i<=m;i++){
char ch[5];scanf("%s",ch);
int x=read(),y=read();
if(ch[0]=='C'){
if(ch[1]=='C'){
change(root[c[x]],1,n,pos[x],0);
c[x]=y;
change(root[c[x]],1,n,pos[x],w[x]);
}
else{change(root[c[x]],1,n,pos[x],y);w[x]=y;}
}
else{
int f=lca(x,y);
if(ch[1]=='S'){
int t=solvesum(c[x],x,f)+solvesum(c[x],y,f);
if(c[x]==c[f])t-=w[f];
printf("%d\n",t);
}
else printf("%d\n",max(solvemx(c[x],x,f),solvemx(c[x],y,f)));
}
}
return 0;
}