```
#include<cstdio>
#include<algorithm>
#include<iostream>
using namespace std;
template<typename T> inline void read(T &x)
{
char ch;
T f=1;
x=0;
do
{
if(ch=='-')
f=-1;
ch=getchar();
}while(!('0'<=ch&&ch<='9'));
do
{
x=(x<<3)+(x<<1)+ch-48;
ch=getchar();
}while('0'<=ch&&ch<='9');
x*=f;
}
const int N=100010;
int wt[N],n;
namespace sgttree
{
#define ls(p) p<<1
#define rs(p) p<<1|1
int ans[N<<2];
inline void pushup(int p)
{
ans[p]=max(ans[ls(p)],ans[rs(p)]);
}
void build(int p,int l,int r)
{
if(l==r)
{
ans[p]=wt[l];
return;
}
int mid=l+r>>1;
build(ls(p),l,mid);
build(rs(p),mid+1,r);
pushup(p);
}
void update(int x,int l,int r,int p,int k)
{
if(l==x&&l==r)
{
ans[p]=k;
return;
}
int mid=l+r>>1;
if(x<=mid)
update(x,l,mid,ls(p),k);
if(mid<x)
update(x,mid+1,r,rs(p),k);
pushup(p);
}
int query(int ql,int qr,int l,int r,int p)
{
if(ql<=l&&r<=qr)
{
return ans[p];
}
int mid=l+r>>1,res=-2147483648;
if(ql<=mid)
res=max(res,query(ql,qr,l,mid,ls(p)));
if(mid<qr)
res=max(res,query(ql,qr,mid+1,r,rs(p)));
return res;
}
}
using namespace sgttree;
namespace treesplit
{
struct edge
{
int nxt,to,w;
#define nxt(n) ed[n].nxt
#define to(n) ed[n].to
#define w(n) ed[n].w
}ed[N<<1];
int hed[N],e,we[N];
int vv[N],uu[N];
int son[N],fa[N],dep[N],id[N],siz[N],top[N],cnt;
inline int add(int u,int v,int w)
{
to(++e)=v;
nxt(e)=hed[u];
w(e)=w;
hed[u]=e;
}
void dfs1(int x,int f,int d)
{
son[x]=0;
dep[x]=d;
fa[x]=f;
siz[x]=1;
int bigson=-1;
for(int i=hed[x];i;i=nxt(i))
{
int y=to(i);
if(y==f)
continue;
we[y]=w(i);
dfs1(y,x,d+1);
siz[x]+=siz[y];
if(bigson<siz[y])
son[x]=y,bigson=siz[y];
}
}
void dfs2(int x,int t)
{
id[x]=++cnt;
wt[cnt]=we[x];
top[x]=t;
if(!son[x])
return;
dfs2(son[x],t);
for(int i=hed[x];i;i=nxt(i))
{
int y=to(i);
if(y==fa[x]||y==son[x])
continue;
dfs2(y,y);
}
}
inline void updedge(int x,int k)
{
static int u=uu[x],v=vv[x];
if(fa[v]==u)
swap(u,v);
update(id[u],1,n,1,k);
}
inline int queryrange(int x,int y)
{
int res=-2147483648;
while(top[x]!=top[y])
{
if(dep[top[x]]<dep[top[y]])
swap(x,y);
res=max(res,query(id[top[x]],id[x],1,n,1));
x=fa[top[x]];
}
if(dep[x]>dep[y])
swap(x,y);
res=max(res,query(id[x]+1,id[y],1,n,1));
return res;
}
}
using namespace treesplit;
int main()
{
read(n);
for(int i=1;i<n;i++)
{
int u,v,w;
read(u);
read(v);
read(w);
uu[i]=u;
vv[i]=v;
add(u,v,w);
add(v,u,w);
}
char ch[10];
int a,b;
dfs1(1,1,1);
dfs2(1,1);
build(1,1,n);
while(1)
{
scanf("%s",ch);
if(ch[0]=='D')
return 0;
read(a);
read(b);
if(ch[0]=='C')
{
updedge(a,b);
}
else
{
printf("%d\n",queryrange(a,b));
}
}
return 0;
}
```
by wxwoo @ 2019-04-12 20:34:46
~~这什么码风~~
~~震惊！行数加倍竟是因为~~
by SSerxhs @ 2019-04-12 20:38:47
这个码风太草了
by NaCly_Fish @ 2019-04-12 20:40:05
~~我手机敲的......粘过来就这样了~~
by wxwoo @ 2019-04-12 20:40:20
这不是手机盲敲猪国杀直接提交还对了的wxwoo吗
by 雪幽幽 @ 2019-04-12 20:45:54