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 }
