[BZOJ 2243][SDOI2011] 染色

  1 #include<cmath>
  2 #include<cstdio>
  3 #include<cstring>
  4 #include<cstdlib>
  5 #include<algorithm>
  6 #include<iostream>
  7 #define N 100100
  8 #define M 200100
  9 using namespace std;
 10 
 11 int n,m,a,b,p;
 12 int color[N],head[N],go[M],next[M];
 13 
 14 void build(int a,int b)
 15 {
 16     go[++p]=b;
 17     next[p]=head[a];
 18     head[a]=p;
 19 }
 20 
 21 struct dfsdata
 22 {
 23     int a,i;
 24     void newdata(int x,int y){a=x;i=y;}
 25 }Stack[N];
 26 
 27 struct makedata
 28 {
 29     int a,i,yes;
 30     void newdata(int x,int y,int z=1){a=x;i=y;yes=z;}
 31 }S[N];
 32 
 33 int tail,f[N],size[N],max_son[N],u,v,deep[N];
 34 
 35 void dfs()
 36 {
 37     int i;
 38     Stack[tail=1].newdata(1,head[1]);f[1]=0;size[1]=1;deep[1]=1;
 39     while (tail)
 40     {
 41         i=Stack[tail].i;v=Stack[tail].a;
 42         if (!i)
 43         {
 44             size[f[v]]+=size[v];
 45             if (size[v]>size[max_son[f[v]]]) max_son[f[v]]=v;
 46             tail--;
 47             continue;
 48         }
 49         u=go[i];
 50         Stack[tail].i=next[i];
 51         if (f[v]!=u)
 52         {
 53             size[u]=1;
 54             f[u]=v;
 55             deep[u]=deep[v]+1;
 56             Stack[++tail].newdata(u,head[u]);
 57         }
 58     }
 59 }
 60 
 61 int L[N],l_deep[N],top[N],len,que[N];
 62 
 63 void make()
 64 {
 65     int i;
 66     S[tail=1].newdata(1,head[1]);L[1]=len=1;l_deep[1]=1;top[1]=1;que[1]=1;
 67     while (tail)
 68     {
 69         v=S[tail].a;i=S[tail].i;
 70         if (!i || size[v]==1){tail--;continue;}
 71         if (S[tail].yes)
 72         {
 73             S[tail].yes=0;
 74             u=max_son[v];
 75             L[u]=++len;
 76             que[len]=u;
 77             l_deep[u]=l_deep[v];
 78             top[u]=top[v];
 79             S[++tail].newdata(u,head[u]);
 80             continue;
 81         }
 82         u=go[i];
 83         S[tail].i=next[i];
 84         if (u!=f[v] && u!=max_son[v])
 85         {
 86             L[u]=++len;
 87             que[len]=u;
 88             l_deep[u]=l_deep[v]+1;
 89             top[u]=u;
 90             S[++tail].newdata(u,head[u]);
 91         }
 92     }
 93 }
 94 
 95 //==========================SegmentTree===========================//
 96 int tree[N<<2],SL[N<<2],SR[N<<2],LZ[N<<2],lazy[N<<2];
 97 
 98 void update(int a)
 99 {
100     tree[a]=tree[a<<1]+tree[(a<<1)+1];
101     SL[a]=SL[a<<1];SR[a]=SR[(a<<1)+1];
102     if (SR[a<<1]==SL[(a<<1)+1]) tree[a]--;
103 }
104 
105 void BuildTree(int p,int l,int r)
106 {
107     if (l==r)
108     {
109         tree[p]=1;
110         SL[p]=SR[p]=color[que[l]];
111         return;
112     }
113     int mid=(l+r)>>1;
114     BuildTree(p<<1,l,mid);
115     BuildTree((p<<1)+1,mid+1,r);
116     update(p);
117 }
118 
119 void Push_down(int a)
120 {
121     if (!LZ[a]) return;
122     LZ[a]=0;
123     LZ[a<<1]=LZ[(a<<1)+1]=1;
124     lazy[a<<1]=lazy[(a<<1)+1]=lazy[a];
125     SL[a<<1]=SR[a<<1]=SL[(a<<1)+1]=SR[(a<<1)+1]=lazy[a];
126     tree[a]=tree[a<<1]=tree[(a<<1)+1]=1;
127 }
128 
129 void Change(int p,int l,int r,int fl,int fr,int c)
130 {
131     if (fl<=l&&r<=fr)
132     {
133         LZ[p]=1;
134         lazy[p]=c;
135         SL[p]=SR[p]=c;
136         tree[p]=1;
137         return;
138     }
139     Push_down(p);
140     int mid=(l+r)>>1;
141     if (fl<=mid) Change(p<<1,l,mid,fl,fr,c);
142     if (fr>mid) Change((p<<1)+1,mid+1,r,fl,fr,c);
143     update(p);
144 }
145 
146 int Query(int p,int l,int r,int fl,int fr,int al,int &x,int ar,int &y)
147 {
148     if (l==fl&&r==fr)
149     {
150         if (LZ[p])
151         {
152             if (l==r)
153             {
154                 LZ[p]=0;
155                 tree[p]=1;
156                 SL[p]=SR[p]=lazy[p];
157             }
158             else Push_down(p),update(p);
159         }
160         if (l==al) x=SL[p];
161         if (r==ar) y=SR[p];
162         return tree[p];
163     }
164     Push_down(p);
165     int mid=(l+r)>>1;
166     if (fr<=mid) return Query(p<<1,l,mid,fl,fr,al,x,ar,y);
167     if (fl>mid) return Query((p<<1)+1,mid+1,r,fl,fr,al,x,ar,y);
168     int ans=Query(p<<1,l,mid,fl,mid,al,x,ar,y)+Query((p<<1)+1,mid+1,r,mid+1,fr,al,x,ar,y);
169     if (SR[p<<1]==SL[(p<<1)+1]) ans--;
170     return ans;
171 }
172 //==========================SegmentTree===========================//
173 
174 void Change(int a,int b,int c)
175 {
176     while (top[a]!=top[b])
177     {
178         if (l_deep[a]<l_deep[b]) swap(a,b);
179         color[a]=c;
180         if (top[a]!=a)
181         {
182             Change(1,1,n,L[top[a]],L[a],c);
183             a=top[a];
184         }
185         else
186         {
187             Change(1,1,n,L[a],L[a],c);
188             a=f[a];
189         }
190     }
191     color[a]=color[b]=c;
192     if (L[a]>L[b]) swap(a,b);
193     Change(1,1,n,L[a],L[b],c);
194 }
195 
196 void Query(int a,int b)
197 {
198     int ans=0,ac=-1,bc=-1,x,y;
199     if (a==b)
200     {
201         printf("1\n");
202         return;
203     }
204     while (top[a]!=top[b])
205     {
206         if (l_deep[a]<l_deep[b]) swap(a,b),swap(ac,bc);
207         if (top[a]!=a)
208         {
209             ans+=Query(1,1,n,L[top[a]]+1,L[a],L[top[a]]+1,x,L[a],y);
210             if (y==ac) ans--;
211             ac=x;
212             a=top[a];
213         }
214         else
215         {
216             ans+=Query(1,1,n,L[a],L[a],L[a],x,L[a],y);
217             if (y==ac) ans--;
218             ac=x;
219             a=f[a];
220         }
221     }
222     if (L[a]>L[b]) swap(a,b),swap(ac,bc);
223     ans+=Query(1,1,n,L[a],L[b],L[a],x,L[b],y);
224     if (x==ac) ans--;
225     if (y==bc) ans--;
226     printf("%d\n",ans);
227 }
228 
229 int main()
230 {
231     scanf("%d%d",&n,&m);
232     for (int i=1;i<=n;i++) scanf("%d",color+i);
233     for (int i=1;i<n;i++)
234     {
235         scanf("%d%d\n",&a,&b);
236         build(a,b);
237         build(b,a);
238     }
239     dfs();
240     make();
241     BuildTree(1,1,n);
242     for (int i=1;i<=m;i++)
243     {
244         char ch;int c;
245         scanf("%c",&ch);
246         if (ch==‘C‘)
247         {
248             scanf("%d%d%d\n",&a,&b,&c);
249             Change(a,b,c);
250         }
251         else
252         {
253             scanf("%d%d\n",&a,&b);
254             Query(a,b);
255         }
256     }
257     return 0;
258 }