POJ - 3321 Apple Tree（树状数组）

 1 /*
 2 * @Author: windystreet
 3 * @Date:   2018-08-02 22:10:44
 4 * @Last Modified by:   windystreet
 5 * @Last Modified time: 2018-08-02 22:56:03
 6 */
 7 #include<stdio.h>
 8 #include<string.h>
 9 #include<algorithm>
10 #include<vector>
11 
12 using namespace std;
13 
14 #define X first
15 #define Y second
16 #define eps  1e-2
17 #define gcd __gcd
18 #define pb push_back
19 #define PI acos(-1.0)
20 #define lowbit(x) (x)&(-x)
21 #define bug printf("!!!!!\n");
22 #define mem(x,y) memset(x,y,sizeof(x))
23 
24 typedef long long LL;
25 typedef long double LD;
26 typedef pair<int,int> pii;
27 typedef unsigned long long uLL;
28 
29 const int maxn = 1e5+7;
30 const LL  INF  = 1<<30;
31 const int mod  = 1e9+7;
32  typedef vector<int> Ve;
33 vector<Ve>G(maxn);
34 int left[maxn],right[maxn],cnt=1,n;
35 int tree[maxn],vis[maxn];
36 
37 int query(int x){
38     int res = 0;
39     while(x){
40         res+=tree[x];
41         x-=lowbit(x);
42     }
43     return res;
44 }
45 void add(int x,int v){
46     for(int i=x;i<=n;i+=lowbit(i)){
47         tree[i]+=v;
48     }
49     return ;
50 }
51 void dfs(int x){
52     left[x] = cnt;                     // 记录左端点的id
53     int sz = G[x].size();
54     for(int i=0;i<sz;i++){
55         cnt++;
56         dfs(G[x][i]);
57     }
58     right[x]=cnt;                      // 记录右端点的id
59 }
60 
61 void solve()
62 {
63     cnt = 1;
64     int x,y,m;
65     char op[3];
66     for(int i=0;i<=n;i++){tree[i]=0;vis[i]=1;G[i].clear();}
67     for(int i=1;i<n;i++){
68         scanf("%d%d",&x,&y);
69         G[x].pb(y);                     // 存图
70     }
71     dfs(1);                             // dfs序
72     for(int i=1;i<=n;i++){
73         add(i,1);                       // 每个点一开始都有一个苹果
74     }
75     scanf("%d",&m);
76     for(int i=0;i<m;i++){
77         scanf("%s%d",op,&x);
78         if(op[0]==‘Q‘){                 // 区间查询
79             printf("%d\n",query(right[x])-query(left[x]-1));
80         }else{
81             if(vis[x])add(left[x],-1);  // 单点修改
82             else add(left[x],1);
83             vis[x]=!vis[x];             // 取反
84         }
85     }
86     return ;
87 }
88 
89 int main()
90 {
91 //    freopen("in.txt","r",stdin);
92 //    freopen("out.txt","w",stdout);
93 //    ios::sync_with_stdio(false);
94     while(scanf("%d",&n)!=EOF){
95     //    printf("Case %d: ",cas++);
96         solve();
97     }
98     return 0;
99 }