bzoj1984 月下“毛景树”(边权的树链剖分)

#include
4000
<bits/stdc++.h>
using namespace std;
#define ll long long
#define inf 0x3f3f3f3f
#define N 100010
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;
}
int n,a
,p
,w
,h
,dep
,fa
,son
,size
,top
,id
,dfn=0;
struct edge{
int to,next,val;
}data[N<<1];
struct node{
int mx,add,cov;
}tree[N<<2];
void dfs1(int x){
size[x]=1;
for(int i=h[x];i;i=data[i].next){
int y=data[i].to;
if(fa[x]==y) continue;
fa[y]=x;dep[y]=dep[x]+1;p[i>>1]=y;a[y]=data[i].val;
dfs1(y);size[x]+=size[y];
if(size[y]>size[son[x]]) son[x]=y;
}
}
void dfs2(int x,int tp){
id[x]=++dfn;top[x]=tp;w[dfn]=a[x];
if(son[x]) dfs2(son[x],tp);
for(int i=h[x];i;i=data[i].next){
int y=data[i].to;
if(y==fa[x]||y==son[x]) continue;
dfs2(y,y);
}
}
inline void pushup(int p){
tree[p].mx=max(tree[p<<1].mx,tree[p<<1|1].mx);
}
inline void pushdown(int p){
if(!tree[p].cov&&!tree[p].add) return;
if(tree[p].cov){
tree[p<<1].cov=tree[p<<1|1].cov=tree[p].cov;
tree[p<<1].mx=tree[p<<1|1].mx=tree[p].cov;
tree[p<<1].add=tree[p<<1|1].add=0;
tree[p].cov=0;
}
if(tree[p].add){
tree[p<<1].add+=tree[p].add;tree[p<<1|1].add+=tree[p].add;
tree[p<<1].mx+=tree[p].add;tree[p<<1|1].mx+=tree[p].add;
tree[p].add=0;
}

}
void build(int p,int l,int r){
if(l==r){tree[p].mx=w[l];return;}
int mid=l+r>>1;
build(p<<1,l,mid);build(p<<1|1,mid+1,r);
pushup(p);
}
void change(int p,int l,int r,int x,int y,int val){
if(x<=l&&r<=y){
tree[p].cov=val;tree[p].mx=val;
tree[p].add=0;return;
}
int mid=l+r>>1;pushdown(p);
if(x<=mid) change(p<<1,l,mid,x,y,val);
if(y>mid) change(p<<1|1,mid+1,r,x,y,val);
pushup(p);
}
void add1(int p,int l,int r,int x,int y,int val){
if(x<=l&&r<=y){
tree[p].add+=val;tree[p].mx+=val;return;
}
int mid=l+r>>1;pushdown(p);
if(x<=mid) add1(p<<1,l,mid,x,y,val);
if(y>mid) add1(p<<1|1,mid+1,r,x,y,val);
pushup(p);
}
int qmax(int p,int l,int r,int x,int y){
if(x<=l&&r<=y){return tree[p].mx;}
int mid=l+r>>1,res=0;pushdown(p);
if(x<=mid) res=max(res,qmax(p<<1,l,mid,x,y));
if(y>mid) res=max(res,qmax(p<<1|1,mid+1,r,x,y));
return res;
}
void dochange(int x,int y,int val){
while(top[x]!=top[y]){
if(dep[top[x]]<dep[top[y]]) swap(x,y);
change(1,1,n,id[top[x]],id[x],val);
x=fa[top[x]];
}
if(id[x]>id[y]) swap(x,y);if(id[x]==id[y]) return;
change(1,1,n,id[x]+1,id[y],val);
}
void doadd(int x,int y,int val){
while(top[x]!=top[y]){
if(dep[top[x]]<dep[top[y]]) swap(x,y);
add1(1,1,n,id[top[x]],id[x],val);
x=fa[top[x]];
}
if(id[x]>id[y]) swap(x,y);if(id[x]==id[y]) return;
add1(1,1,n,id[x]+1,id[y],val);
}
int domax(int x,int y){
int res=0;
while(top[x]!=top[y]){
if(dep[top[x]]<dep[top[y]]) swap(x,y);
res=max(res,qmax(1,1,n,id[top[x]],id[x]));
x=fa[top[x]];
}
if(id[x]>id[y]) swap(x,y);if(id[x]==id[y]) return res;
return max(res,qmax(1,1,n,id[x]+1,id[y]));
}
int main(){
//  freopen("a.in","r",stdin);
n=read();
for(int i=1;i<n;++i){
int x=read(),y=read(),v=read();
data[i<<1].to=y;data[i<<1].next=h[x];h[x]=i<<1;data[i<<1].val=v;
data[i<<1|1].to=x;data[i<<1|1].next=h[y];h[y]=i<<1|1;data[i<<1|1].val=v;
}
dep[1]=1;dfs1(1);dfs2(1,1);build(1,1,n);
while(1){
char op[10];scanf("%s",op+1);
if(op[2]=='t') break;int x=read(),y=read();
if(op[2]=='h') change(1,1,n,id[p[x]],id[p[x]],y);
if(op[2]=='o') dochange(x,y,read());
if(op[2]=='d') doadd(x,y,read());
if(op[2]=='a') printf("%d\n",domax(x,y));
}
return 0;
}