纪念一下独立AC紫题。
最近在学树剖，就忘了差分了……所以效率比较低
#include <iostream>
#include <cstdio>
using namespace std;
int n, uu, vv, a[300005], hea[300005], dep[300005], gnd[300005][21], qwq;
int siz[300005], son[300005], top[300005], cnt, idx[300005], ans[300005];
struct Edge{
int too, nxt;
}edge[600005];
struct SGT{
int sum[1200005];
int tag[1200005];
void pushDown(int o, int l, int r, int lson, int rson, int mid){
tag[lson] += tag[o];
tag[rson] += tag[o];
sum[lson] += (mid-l+1) * tag[o];
sum[rson] += (r-mid) * tag[o];
tag[o] = 0;
}
void update(int o, int l, int r, int x, int y, int k){
if(l>=x && r<=y){
sum[o] += (r-l+1) * k;
tag[o] += k;
}
else{
int mid=(l+r)>>1;
int lson=o<<1;
int rson=lson|1;
if(tag[o]) pushDown(o, l, r, lson, rson, mid);
if(x<=mid) update(lson, l, mid, x, y, k);
if(mid<y) update(rson, mid+1, r, x, y, k);
sum[o] = sum[lson] + sum[rson];
}
}
void func(int o, int l, int r){
if(l==r) ans[l] += sum[o];
else{
int mid=(l+r)>>1;
int lson=o<<1;
int rson=lson|1;
if(tag[o]) pushDown(o, l, r, lson, rson, mid);
if(l<=mid) func(lson, l, mid);
if(mid<r) func(rson, mid+1, r);
}
}
}sgt;
void add_edge(int fro, int too){
edge[++cnt].nxt = hea[fro];
edge[cnt].too = too;
hea[fro] = cnt;
}
void dfs1(int x, int f){
gnd[x][0] = f;
dep[x] = dep[f] + 1;
siz[x] = 1;
int maxSon=-1;
for(int i=hea[x]; i; i=edge[i].nxt){
int t=edge[i].too;
if(t==f) continue;
dfs1(t, x);
siz[x] += siz[t];
if(siz[t]>maxSon){
maxSon = siz[t];
son[x] = t;
}
}
}
void dfs2(int x, int topf){
top[x] = topf;
idx[x] = ++qwq;
if(!son[x]) return ;
dfs2(son[x], topf);
for(int i=hea[x]; i; i=edge[i].nxt){
int t=edge[i].too;
if(t==gnd[x][0] || t==son[x]) continue;
dfs2(t, t);
}
}
int getLca(int xx, int yy){
while(top[xx]!=top[yy]){
if(dep[top[xx]]<dep[top[yy]]) swap(xx, yy);
xx = gnd[top[xx]][0];
}
return dep[xx]>dep[yy]?yy:xx;
}
void updRange(int uu, int vv){
while(top[uu]!=top[vv]){
if(dep[top[uu]]<dep[top[vv]]) swap(uu, vv);
sgt.update(1, 1, n, idx[top[uu]], idx[uu], 1);
uu = gnd[top[uu]][0];
}
if(dep[uu]>dep[vv]) swap(uu, vv);
sgt.update(1, 1, n, idx[uu], idx[vv], 1);
}
int main(){
cin>>n;
for(int i=1; i<=n; i++)
scanf("%d", &a[i]);
for(int i=1; i<n; i++){
scanf("%d %d", &uu, &vv);
add_edge(uu, vv);
add_edge(vv, uu);
}
dep[1] = 1;
dfs1(1, 0);
dfs2(1, 1);
for(int i=1; i<n; i++){
uu = a[i];
vv = a[i+1];
int lca=getLca(uu, vv);
ans[idx[lca]]--;
updRange(uu, lca);
updRange(vv, lca);
}
sgt.func(1, 1, n);
for(int i=2; i<=n; i++)
ans[idx[a[i]]]--;
for(int i=1; i<=n; i++)
printf("%d
", ans[idx[i]]);
return 0;
}