[Noi2015]软件包管理器 题解

  1 #include<cstdio>
  2 #include<iostream>
  3 #define M 800500
  4 using namespace std;
  5 
  6 int n,cnt,dfn,hson[M],pa[M],id[M],to[M],top[M],vis[M],last[M],next[M],head[M],deep[M],size[M],sum[M],sz[M],lazy[M];
  7 
  8 void ins(int x,int y)
  9 {
 10      to[++cnt]=y,next[cnt]=head[x],head[x]=cnt;
 11 }
 12 
 13 void dfs1(int x)
 14 {
 15     size[x]=1;
 16     for (int i=head[x];i;i=next[i])
 17         if (to[i]!=pa[x])
 18         {
 19             pa[to[i]]=x,deep[to[i]]=deep[x]+1;
 20             dfs1(to[i]),size[x]+=size[to[i]];
 21             if (size[to[i]]>size[hson[x]]) hson[x]=to[i];
 22         }
 23 }
 24 
 25 void dfs2(int x,int tp)
 26 {
 27     id[x]=++dfn,top[x]=tp;
 28     if (hson[x]) dfs2(hson[x],tp);
 29     for (int i=head[x];i;i=next[i])
 30         if (to[i]!=pa[x]&&to[i]!=hson[x]) dfs2(to[i],to[i]);
 31     last[x]=dfn;
 32 }
 33 
 34 void build(int l,int r,int cur)
 35 {
 36      if (l==r) { sum[cur]=0,lazy[cur]=-1,sz[cur]=1; return; }
 37      int mid=l+r>>1;
 38      build(l,mid,cur<<1),build(mid+1,r,cur<<1|1);
 39      sz[cur]=sz[cur<<1]+sz[cur<<1|1];
 40 }
 41 
 42 void push_down(int k)
 43 {
 44      if (lazy[k]!=-1)
 45      {
 46           sum[k<<1]=sz[k<<1]*lazy[k],sum[k<<1|1]=sz[k<<1|1]*lazy[k];
 47           lazy[k<<1]=lazy[k<<1|1]=lazy[k],lazy[k]=-1;
 48      }
 49 }
 50 
 51 void change(int L,int R,int l,int r,int cur,int val)
 52 {
 53      if (L==l && R==r) { sum[cur]=val*sz[cur]; lazy[cur]=val; return; }
 54      int mid=L+R>>1; push_down(cur);
 55      if (r<=mid) change(L,mid,l,r,cur<<1,val);
 56      else if (l>mid) change(mid+1,R,l,r,cur<<1|1,val);
 57           else change(L,mid,l,mid,cur<<1,val),change(mid+1,R,mid+1,r,cur<<1|1,val);
 58      sum[cur]=sum[cur<<1]+sum[cur<<1|1];
 59 }
 60 
 61 int ask(int L,int R,int l,int r,int cur)
 62 {
 63     if (L==l && R==r) return sum[cur];
 64     int mid=L+R>>1; push_down(cur);
 65     if (r<=mid) return ask(L,mid,l,r,cur<<1);
 66     else if (l>mid) return ask(mid+1,R,l,r,cur<<1|1);
 67          else return ask(L,mid,l,mid,cur<<1)+ask(mid+1,R,mid+1,r,cur<<1|1);
 68 }
 69 
 70 void add(int x,int y)
 71 {
 72      if (deep[x]<deep[y]) swap(x,y);
 73      int sum=0,t=deep[x]-deep[y]+1;
 74      for (;top[x]!=top[y];x=pa[top[x]])
 75      {         
 76          if (deep[top[x]]<deep[top[y]]) swap(x,y);
 77          sum+=ask(1,n,id[top[x]],id[x],1);
 78          change(1,n,id[top[x]],id[x],1,1);
 79      }
 80      if (deep[x]>deep[y]) swap(x,y);
 81      sum+=ask(1,n,id[x],id[y],1);
 82      change(1,n,id[x],id[y],1,1);
 83      printf("%d\n",t-sum);
 84 }
 85 
 86 int main()
 87 {
 88     int i,m,x;
 89     scanf("%d",&n);
 90     for (i=1;i<n;i++) scanf("%d",&m),ins(m+1,i+1);
 91     scanf("%d",&m),dfs1(1),dfs2(1,1),build(1,n,1);
 92     for (i=1;i<=m;i++)
 93     {
 94         char ch[20];
 95         scanf("%s%d",ch,&x),x++;
 96         if (ch[0]==‘i‘) add(1,x);
 97         else printf("%d\n",ask(1,n,id[x],last[x],1)),change(1,n,id[x],last[x],1,0);
 98     }
 99     return 0;
100 }