dfs序 

  1 /*
  2   Source   : POJ 3321
  3   Problem  : 每次改变树的点权，求子树点权和
  4   Solution : dfs序
  5   Date     :2018-08-16-16.03
  6 */
  7 
  8 // #include <bits/stdc++.h>
  9 #include <cstdio>
 10 #include <cstring>
 11 #include <cstdlib>
 12 #include <iostream>
 13 #include <vector>
 14 using namespace std;
 15 
 16 typedef long long LL;
 17 const int MAXN = 100005;
 18 const LL MOD7 = 1e9+7;
 19 
 20 inline int read()
 21 {
 22     int x=0;char ch=getchar();
 23     while (ch<'0' || ch>'9') ch=getchar();
 24     while (ch>='0' && ch<='9') x=x*10+ch-'0',ch=getchar();
 25     return x;
 26 }
 27 
 28 
 29 struct Edge
 30 {
 31     int u,v;
 32     int next;
 33 }edge[2*MAXN];
 34 int head[MAXN];
 35 int cnt;
 36 
 37 // vector<int> g[MAXN];
 38 int n;
 39 int in[MAXN];
 40 int out[MAXN];
 41 int pos[MAXN];
 42 int a[MAXN];
 43 int Clock;
 44 int f[2*MAXN];
 45 
 46 void dfs(int u, int pre)
 47 {
 48     in[u]=++Clock;
 49     pos[Clock]=u;
 50     for (int i=head[u];i!=-1;i=edge[i].next)
 51     {
 52         int v=edge[i].v;
 53         if (v==pre) continue;
 54         dfs(v,u);
 55     }
 56     out[u]=Clock;
 57 }
 58 
 59 void init()
 60 {
 61     memset(f,0,sizeof(f));
 62     memset(head,-1,sizeof(head));
 63     cnt=0;
 64 }
 65 
 66 void addEdge(int u,int v)
 67 {
 68     edge[cnt].u=u;edge[cnt].v=v;edge[cnt].next=head[u];head[u]=cnt++;
 69 }
 70 
 71 inline int lowbit(int x)
 72 {
 73     return x&(-x);
 74 }
 75 
 76 void update(int x, int c)
 77 {
 78     while (x<=Clock)
 79     {
 80         f[x]+=c;
 81         x+=lowbit(x);
 82     }
 83 }
 84 
 85 int query(int x)
 86 {
 87     int sum=0;
 88     for (;x;sum+=f[x],x-=lowbit(x));
 89     return sum;
 90 }
 91 
 92 int main()
 93 {
 94 #ifndef ONLINE_JUDGE
 95     freopen("test.txt","r",stdin);
 96 #endif // ONLINE_JUDGE
 97     scanf("%d",&n);
 98     {
 99         int u,v;
100         // for (int i=1;i<=n;++i) g[i].clear();
101         init();
102         for (int i=1;i<n;++i)
103         {
104             u=read();v=read();
105             // g[u].push_back(v);
106             // g[v].push_back(u);
107             addEdge(u, v);
108             addEdge(v, u);
109         }
110         Clock=0;
111         dfs(1,-1);
112         // init();
113         for (int i=1;i<=n;++i) update(in[i],1),a[i]=1;
114         int Q;
115         scanf("%d",&Q);
116         char op[5];
117         for (int i=1;i<=Q;++i)
118         {
119             scanf("%s%d",op,&u);
120             if (op[0]=='C')
121             {
122                 update(in[u],-1*a[u]);
123                 a[u]*=-1;
124             }
125             else
126             {
127                 printf("%d\n",query(out[u])-query(in[u]-1));
128             }
129         }
130     }
131     return 0;
132 }

 

posted @ 2018-08-16 16:36  LeeSongt  阅读(180)  评论(0)    收藏  举报