BZOJ3631[JLOI2014]松鼠的新家 题解

  1 #include<cstdio>
  2 #include<cstring>
  3 #include<iostream>
  4 #include<algorithm>
  5 #define M 1200000
  6 using namespace std;
  7 
  8 int ans[M],to[M],head[M],next[M],vis[M],size[M],deep[M],id[M],top[M],sum[M],fa[M],a[M],cnt,dfn,n;
  9 
 10 void add(int x,int y)
 11 {
 12     to[++cnt]=y;
 13     next[cnt]=head[x];
 14     head[x]=cnt;
 15 }
 16 
 17 void dfs1(int x)
 18 {
 19     size[x]=vis[x]=1;
 20     for (int i=head[x];i;i=next[i])
 21         if (!vis[to[i]])
 22         {
 23             deep[to[i]]=deep[x]+1;
 24             fa[to[i]]=x;
 25             dfs1(to[i]);
 26             size[x]+=size[to[i]];
 27         }
 28 }
 29 
 30 void dfs2(int x,int chain)
 31 {
 32     int k=0,i;
 33     id[x]=++dfn;
 34     top[x]=chain;
 35     for (i=head[x];i;i=next[i])
 36         if (deep[to[i]]>deep[x] && size[to[i]]>size[k]) k=to[i];
 37     if (!k) return;
 38     dfs2(k,chain);
 39     for (i=head[x];i;i=next[i])
 40         if (deep[to[i]]>deep[x] && to[i]!=k) dfs2(to[i],to[i]);
 41 }
 42 
 43 void push_down(int cur)
 44 {
 45     sum[cur<<1]+=sum[cur];
 46     sum[cur<<1|1]+=sum[cur];
 47     sum[cur]=0;
 48 }
 49 
 50 void ADD(int L,int R,int l,int r,int cur)
 51 {
 52     if (l<=L && r>=R)
 53     {
 54         sum[cur]++;
 55         return;
 56     }
 57     push_down(cur);
 58     int mid=L+R>>1;
 59     if (l>mid) ADD(mid+1,R,l,r,cur<<1|1);
 60     else if (r<=mid) ADD(L,mid,l,r,cur<<1);
 61          else ADD(L,mid,l,mid,cur<<1),ADD(mid+1,R,mid+1,r,cur<<1|1);
 62 }
 63 
 64 int ask(int l,int r,int x,int cur)
 65 {
 66     if (l==r) return sum[cur];
 67     push_down(cur);
 68     int mid=l+r>>1;
 69     if (x>mid) return sum[cur]+ask(mid+1,r,x,cur<<1|1);
 70     else return sum[cur]+ask(l,mid,x,cur<<1);
 71 }
 72 
 73 void Add(int x,int y)
 74 {
 75     for (;top[x]!=top[y];x=fa[top[x]])
 76     {
 77         if (deep[top[x]]<deep[top[y]]) swap(x,y);
 78         ADD(1,n,id[top[x]],id[x],1);
 79     }
 80     if (deep[x]<deep[y]) swap(x,y);
 81     ADD(1,n,id[y],id[x],1);
 82 }
 83 
 84 int main()
 85 {
 86     int i,x,y;
 87     scanf("%d",&n);
 88     for (i=1;i<=n;i++) scanf("%d",&a[i]);
 89     for (i=1;i<n;i++) scanf("%d%d",&x,&y),add(x,y),add(y,x);
 90     dfs1(1);
 91     dfs2(1,1);
 92     for (i=1;i<n;i++) Add(a[i],a[i+1]);
 93     for (i=1;i<=n;i++)
 94     {
 95         ans[i]=-(i!=a[1]);
 96         ans[i]+=ask(1,n,id[i],1);
 97     }
 98     for (i=1;i<=n;i++) printf("%d\n",ans[i]);
 99     return 0;
100 }