HDU 5156 - Harry and Christmas tree (dfs序+离线树状数组)

  1 #include <iostream>
  2 #include <sstream>
  3 #include <ios>
  4 #include <iomanip>
  5 #include <functional>
  6 #include <algorithm>
  7 #include <vector>
  8 #include <string>
  9 #include <list>
 10 #include <queue>
 11 #include <deque>
 12 #include <stack>
 13 #include <set>
 14 #include <map>
 15 #include <cstdio>
 16 #include <cstdlib>
 17 #include <cmath>
 18 #include <cstring>
 19 #include <climits>
 20 #include <cctype>
 21 using namespace std;
 22 #define XINF INT_MAX
 23 #define INF 0x3FFFFFFF
 24 #define MP(X,Y) make_pair(X,Y)
 25 #define PB(X) push_back(X)
 26 #define REP(X,N) for(int X=0;X<N;X++)
 27 #define REP2(X,L,R) for(int X=L;X<=R;X++)
 28 #define DEP(X,R,L) for(int X=R;X>=L;X--)
 29 #define CLR(A,X) memset(A,X,sizeof(A))
 30 #define IT iterator
 31 #define RIT reverse_iterator
 32 typedef long long ll;
 33 typedef unsigned long long ull;
 34 typedef pair<int,int> PII;
 35 typedef vector<PII> VII;
 36 typedef vector<int> VI;
 37 #define X first
 38 #define Y second
 39 #define lson(X) ((X)<<1)
 40 #define rson(X) ((X)<<1|1)
 41 
 42 int Scan()
 43 {
 44     int res, ch=0;
 45     while(!(ch>=‘0‘&&ch<=‘9‘)) ch=getchar();
 46     res=ch-‘0‘;
 47     while((ch=getchar())>=‘0‘&&ch<=‘9‘)
 48         res=res*10+ch-‘0‘;
 49     return res;
 50 }
 51 
 52 void Out(int a)
 53 {
 54     if(a>9)
 55         Out(a/10);
 56     putchar(a%10+‘0‘);
 57 }
 58 
 59 
 60 int c[500010];
 61 int N;
 62 
 63 void init(int n) {
 64     N = n;
 65     REP(i,N+1) c[i]=0;
 66 }
 67 
 68 void add(int i, int x) {
 69     while(i<=N) {
 70         c[i]+=x;
 71         i+=i&-i;
 72     }
 73 }
 74 
 75 int sum(int i) {
 76     int r=0;
 77     while(i) {
 78         r+=c[i];
 79         i-=i&-i;
 80     }
 81     return r;
 82 }
 83 
 84 int a[500010];
 85 
 86 int ans[50000];
 87 VII query[500010];
 88 
 89 VI Map[50000];
 90 int vis[50000];
 91 int s[50000], e[50000];
 92 VI vec[50000];
 93 
 94 int tot=0;
 95 void dfs(int u) {
 96     vis[u]=1;
 97     s[u]=tot;
 98     REP(i,vec[u].size()) a[tot++]=vec[u][i];
 99     REP(i,Map[u].size()) {
100         int v=Map[u][i];
101         if(!vis[v]) dfs(v);
102     }
103     e[u]=tot-1;
104 }
105 
106 int mp[100001]; // 此处如果改用map会慢很多 
107 
108 int main() {
109     int n,m,l,r,u,v;
110     while(~scanf("%d%d",&n,&m)) {
111         REP(i,50000) Map[i].clear();
112         REP(i,50000) vec[i].clear();
113         REP(i,n-1) {
114             u=Scan(); v=Scan();
115             u--; v--;
116             Map[u].PB(v);
117             Map[v].PB(u);
118         }
119         REP(i,m) {
120             u=Scan(); v=Scan();
121             u--;
122             vec[u].PB(v);
123         }
124         /* 对一个节点上的颜色去重 
125         REP(i,n) {
126             sort(vec[i].begin(),vec[i].end());
127             vec[i].erase(unique(vec[i].begin(),vec[i].end()),vec[i].end());
128         }
129         */
130         tot=1;
131         CLR(vis,0);
132         dfs(0);
133         
134         REP(i,tot) query[i].clear();
135         REP(i,n) query[s[i]].PB(MP(e[i],i));
136         //map<int,int> mp;
137         CLR(mp,-1);
138         init(tot);
139         DEP(i,tot,1) {
140             add(i,1);
141             if(mp[a[i]]!=-1) add(mp[a[i]],-1);
142             REP(j,query[i].size()) {
143                 ans[query[i][j].Y] = sum(query[i][j].X);
144             }
145             mp[a[i]]=i;
146         }
147         REP(i,n) {
148             if(i) putchar(‘ ‘);
149             Out(ans[i]);
150         }
151         putchar(‘\n‘);
152     }
153     return 0;
154 }