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| #include<cstdio>
using namespace std;
const int inf=0x3f3f3f3f;
int n,q,val[30001];
int tot,fir[30001],fa[30001],dep[30001],siz[30001],hson[30001],dfn[30001],rnk[30001],top[30001];
struct edge {
int to;
int nex;
}e[59999];
struct seg_tree {
int l,r,maxn,sum;
}t[120001];
inline int max(int x,int y)
{
return x>=y?x:y;
}
inline void add(int u,int v)
{
e[++tot]=edge{v,fir[u]};
fir[u]=tot;
return;
}
void dfs1(int u,int fa)
{
::fa[u]=fa,dep[u]=dep[fa]+1,siz[u]=1;
for(int i=fir[u],v;v=e[i].to,i;i=e[i].nex) {
if(v==fa) {
continue;
}
dfs1(v,u);
siz[u]+=siz[v],hson[u]=siz[v]>siz[hson[u]]?v:hson[u];
}
return;
}
void dfs2(int u,int top)
{
::top[u]=top,dfn[u]=++tot,rnk[tot]=u;
if(hson[u]) {
dfs2(hson[u],top);
}
for(int i=fir[u],v;v=e[i].to,i;i=e[i].nex) {
if((v==fa[u])||(v==hson[u])) {
continue;
}
dfs2(v,v);
}
return;
}
void build(int num,int l,int r)
{
t[num]=seg_tree{l,r,0,0};
if(l==r) {
t[num].maxn=t[num].sum=val[rnk[l]];
return;
}
int mid=(l+r)>>1;
build(num<<1,l,mid),build(num<<1|1,mid+1,r);
t[num].maxn=max(t[num<<1].maxn,t[num<<1|1].maxn),t[num].sum=t[num<<1].sum+t[num<<1|1].sum;
return;
}
void change(int num,int pos,int val)
{
if((t[num].l>pos)||(t[num].r<pos)) {
return;
}
if((t[num].l==pos)&&(t[num].r==pos)) {
t[num].maxn=t[num].sum=val;
return;
}
change(num<<1,pos,val),change(num<<1|1,pos,val);
t[num].maxn=max(t[num<<1].maxn,t[num<<1|1].maxn),t[num].sum=t[num<<1].sum+t[num<<1|1].sum;
return;
}
int get_max(int num,int l,int r)
{
if((t[num].l>r)||(t[num].r<l)) {
return -inf;
}
if((t[num].l>=l)&&(t[num].r<=r)) {
return t[num].maxn;
}
return max(get_max(num<<1,l,r),get_max(num<<1|1,l,r));
}
int get_sum(int num,int l,int r)
{
if((t[num].l>r)||(t[num].r<l)) {
return 0;
}
if((t[num].l>=l)&&(t[num].r<=r)) {
return t[num].sum;
}
return get_sum(num<<1,l,r)+get_sum(num<<1|1,l,r);
}
void Change()
{
int u,t;
scanf("%d%d",&u,&t);
change(1,dfn[u],t);
return;
}
void Max()
{
int u,v,res=-inf;
scanf("%d%d",&u,&v);
while(top[u]!=top[v]) {
if(dep[top[u]]>dep[top[v]]) {
res=max(res,get_max(1,dfn[top[u]],dfn[u]));
u=fa[top[u]];
} else {
res=max(res,get_max(1,dfn[top[v]],dfn[v]));
v=fa[top[v]];
}
}
res=max(res,dep[u]>dep[v]?get_max(1,dfn[v],dfn[u]):get_max(1,dfn[u],dfn[v]));
printf("%d\n",res);
return;
}
void Sum()
{
int u,v,res=0;
scanf("%d%d",&u,&v);
while(top[u]!=top[v]) {
if(dep[top[u]]>dep[top[v]]) {
res+=get_sum(1,dfn[top[u]],dfn[u]);
u=fa[top[u]];
} else {
res+=get_sum(1,dfn[top[v]],dfn[v]);
v=fa[top[v]];
}
}
res+=dep[u]>dep[v]?get_sum(1,dfn[v],dfn[u]):get_sum(1,dfn[u],dfn[v]);
printf("%d\n",res);
return;
}
int main()
{
scanf("%d",&n);
for(int i=1,u,v;i<n;++i) {
scanf("%d%d",&u,&v);
add(u,v),add(v,u);
}
dfs1(1,1);
tot=0,dfs2(1,1);
for(int i=1;i<=n;++i) {
scanf("%d",&val[i]);
}
build(1,1,n);
scanf("%d",&q);
while(q--) {
char s[10];
scanf("%s",s);
if(s[0]=='C') {
Change();
} else {
if(s[1]=='M') {
Max();
} else {
Sum();
}
}
}
return 0;
}
|