bzoj 1086: [SCOI2005]王室联邦

神题,树分块的基础的233,,,反正就是神奇的乱搜,不会

 1 #include<bits/stdc++.h>
 2 #define N 100005
 3 #define LL long long
 4 #define inf 0x3f3f3f3f
 5 using namespace std;
 6 inline int ra()
 7 {
 8     int x=0,f=1; char ch=getchar();
 9     while (ch<'0' || ch>'9') {if (ch=='-') f=-1; ch=getchar();}
10     while (ch>='0' && ch<='9') {x=x*10+ch-'0'; ch=getchar();}
11     return x*f;
12 }
13 struct node{int to,next;}e[N];
14 int n,b,top,s[N],belong[N],root[N],head[N],cnt1,cnt;
15 void insert(int x, int y){e[++cnt1].next=head[x]; e[cnt1].to=y; head[x]=cnt1;}
16 void dfs(int x, int fa)
17 {
18     /*int size=0;
19     for (int i=head[x];i;i=e[i].next)
20     {
21         if (e[i].to==fa) continue;
22         size+=dfs(e[i].to,x);
23         if (size>=b)
24         {
25             ++cnt;
26             while (size--) belong[s[top--]]=cnt;
27             root[cnt]=x;
28         } 
29     }
30     s[++top]=x;
31     return size+1;*/
32     int bottom=top;
33     for (int i=head[x];i;i=e[i].next)
34     {
35         if (e[i].to==fa) continue;
36         dfs(e[i].to,x);
37         if (top-bottom>=b)
38         {
39             root[++cnt]=x;
40             while (top!=bottom) belong[s[top--]]=cnt;
41         }
42     }
43     s[++top]=x;
44 }
45 int main()
46 {
47     n=ra(); b=ra(); 
48     if (n<b)
49     {
50         printf("0");
51         return 0;
52     }
53     for (int i=1; i<n; i++)
54     {
55         int x=ra(),y=ra();
56         insert(x,y); insert(y,x);
57     }
58     dfs(1,0);
59     while (top) belong[s[top--]]=cnt;
60     cout<<cnt<<endl;
61     for (int i=1; i<=n; i++)
62         printf("%d ",belong[i]); cout<<endl;
63     for (int i=1; i<=cnt; i++)
64         printf("%d ",root[i]);
65     return 0;
66 }

 

posted @ 2017-02-23 21:30  ws_ccd  阅读(...)  评论(... 编辑 收藏