发现自己Tarjan的板子有错误.发现可以用Map直接删去边，Get.
听说std是双连通、LCA、并查集、离线思想、用BIT维护dfs序和并查集维护LCA的动态缩点的好题
1 #include <iostream>
2 #include <cstring>
3 #include <cstdio>
4 #include <algorithm>
5 #include <vector>
6 #include <map>
7 #include <set>
8 #include <stack>
9 #define mp make_pair
10 #define pa pair<int,int>
11 #define pb push_back
12 #define fi first
13 #define se second
14 using namespace std;
15 inline void Get_Int(int &x)
16 {
17 x=0; char ch=getchar(); int f=1;
18 while (ch<‘0‘ || ch>‘9‘) {if (ch==‘-‘) f=-1; ch=getchar();}
19 while (ch>=‘0‘ && ch<=‘9‘) {x=x*10+ch-‘0‘; ch=getchar();} x*=f;
20 }
21 inline void Put_Int(int x)
22 {
23 char ch[20]; int top=0;
24 if (x==0) ch[++top]=‘0‘;
25 while (x) ch[++top]=x%10+‘0‘,x/=10;
26 while (top) putchar(ch[top--]); putchar(‘\n‘);
27 }
28 //===================================================
29 const int Maxm=200100;
30 const int Maxn=30100;
31 const int Maxop=40100;
32 struct EDGE{int to,next;}edge[Maxm];
33 struct OP{int type,u,v;}Op[Maxop];
34 int head[Maxn],siz[Maxn],father[Maxn],top[Maxn],dep[Maxn],num[Maxn],sum[Maxn<<2],clr[Maxn<<2];
35 int Belong[Maxn],Low[Maxn],Dfn[Maxn],Ans[Maxn];
36 int Stack[Maxn];
37 int stamp,Stamp,cnt,scc,apex,Q,n,m,u,v;
38 bool vis[Maxn];
39 map<pa,bool> Edge;
40 vector<pa> V;
41 set <pa> S;
42 inline void Add(int u,int v)
43 {edge[cnt].to=v;edge[cnt].next=head[u];head[u]=cnt++;}
44 inline int Max(int x,int y) {return x>y?x:y;}
45 inline int Min(int x,int y) {return x>y?y:x;}
46 inline void Build_G()
47 {
48 map<pa,bool>::iterator it;
49 for (it=Edge.begin();it!=Edge.end();it++)
50 if (it->se)
51 Add(it->fi.fi,it->fi.se);
52 }
53 inline void Clear_G()
54 {
55 map<pa,bool>::iterator it;
56 for (it=Edge.begin();it!=Edge.end();it++)
57 if (it->se) it->se=false;
58 }
59 //=================================================
60
61 void Dfs1(int u)
62 {
63 vis[u]=true; siz[u]=1;
64 for (int i=head[u];i!=-1;i=edge[i].next)
65 if (!vis[edge[i].to])
66 {
67 father[edge[i].to]=u;
68 dep[edge[i].to]=dep[u]+1;
69 Dfs1(edge[i].to);
70 siz[u]+=siz[edge[i].to];
71 }
72 }
73 void Dfs2(int u,int chain)
74 {
75 num[u]=++stamp; top[u]=chain; vis[u]=true; int k=0;
76 for (int i=head[u];i!=-1;i=edge[i].next)
77 if (!vis[edge[i].to] && (siz[edge[i].to]>siz[k] || k==0)) k=edge[i].to;
78 if (k==0) return;
79 Dfs2(k,chain);
80 for (int i=head[u];i!=-1;i=edge[i].next)
81 if (!vis[edge[i].to] && edge[i].to!=k) Dfs2(edge[i].to,edge[i].to);
82 }
83
84 inline int Lca(int u,int v)
85 {
86 while (true)
87 {
88 if (top[u]==top[v]) return dep[u]>dep[v]?v:u;
89 if (dep[top[u]]>dep[top[v]]) u=father[top[u]]; else v=father[top[v]];
90 }
91 }
92 //==================================================
93
94 inline void push_up(int o) {sum[o]=sum[o<<1]+sum[o<<1|1];}
95 inline void Clr(int o) {clr[o]=1; sum[o]=0;}
96 inline void push_down(int o) {if (clr[o]) Clr(o<<1),Clr(o<<1|1); clr[o]=0;}
97 void Modify(int o,int l,int r,int p,int q)
98 {
99 if (l==p && r==q)
100 {
101 sum[o]=0;
102 clr[o]=1;
103 return;
104 }
105 push_down(o);
106 int mid=(l+r)>>1;
107 if (q<=mid) Modify(o<<1,l,mid,p,q);
108 if (p>=mid+1) Modify(o<<1|1,mid+1,r,p,q);
109 if (p<=mid && q>=mid+1) Modify(o<<1,l,mid,p,mid),Modify(o<<1|1,mid+1,r,mid+1,q);
110 push_up(o);
111 }
112 int Query(int o,int l,int r,int p,int q)
113 {
114 if (l==p && r==q) return sum[o];
115 push_down(o);
116 int mid=(l+r)>>1;
117 if (q<=mid) return Query(o<<1,l,mid,p,q);
118 if (p>=mid+1) return Query(o<<1|1,mid+1,r,p,q);
119 if (p<=mid && q>=mid+1) return Query(o<<1,l,mid,p,mid)+Query(o<<1|1,mid+1,r,mid+1,q);
120 }
121 void Build(int o,int l,int r)
122 {
123 if (l==r)
124 {
125 sum[o]=1;
126 return;
127 }
128 int mid=(l+r)>>1;
129 Build(o<<1,l,mid),Build(o<<1|1,mid+1,r);
130 push_up(o);
131 }
132
133 //=================================================
134 void Tree_Modify(int u,int v)
135 {
136 while (top[u]!=top[v])
137 {
138 Modify(1,1,scc,num[top[u]],num[u]);
139 u=father[top[u]];
140 }
141 Modify(1,1,scc,num[v],num[u]);
142 }
143 int Tree_Query(int u,int v)
144 {
145 int ret=0;
146
147 while (top[u]!=top[v])
148 {
149 ret+=Query(1,1,scc,num[top[u]],num[u]);
150 u=father[top[u]];
151 }
152 ret+=Query(1,1,scc,num[v],num[u]);
153 return ret;
154 }
155 //=================================================
156 void Tarjan(int u,int fa)
157 {
158 Low[u]=Dfn[u]=++Stamp; Stack[++apex]=u;
159 for(int i=head[u];i!=-1;i=edge[i].next)
160 if (edge[i].to!=fa)
161 {
162 int v=edge[i].to;
163 if(!Dfn[v])
164 {
165 Tarjan(v,u);
166 Low[u]=Min(Low[u],Low[v]);
167 if(Low[v]>Dfn[u])
168 {
169 scc++;
170 while(true) {int x=Stack[apex--]; Belong[x]=scc; if(x==v)break;}
171 }
172 }
173 else Low[u]=Min(Low[u],Dfn[v]);
174 }
175 if(fa<0)
176 {
177 scc++;
178 while(true){int x=Stack[apex--]; Belong[x]=scc; if(x==u)break;}
179 }
180 }
181 //=================================================
182
183 int main()
184 {
185 //freopen("c.in","r",stdin);
186 Get_Int(n),Get_Int(m);
187 for (int i=1;i<=m;i++)
188 Get_Int(u),Get_Int(v),Edge[mp(u,v)]=true,Edge[mp(v,u)]=true;
189
190 for (Q=1;;Q++)
191 {
192 Get_Int(Op[Q].type); if (Op[Q].type==-1) break;
193 Get_Int(Op[Q].u),Get_Int(Op[Q].v);
194 if (Op[Q].type==0) Edge[mp(Op[Q].u,Op[Q].v)]=false,Edge[mp(Op[Q].v,Op[Q].u)]=false;
195 }
196 Q--;
197 stamp=Stamp=cnt=0;
198 memset(head,-1,sizeof(head));
199 memset(vis,false,sizeof(vis));
200 memset(Low,0,sizeof(Low));
201 memset(Dfn,0,sizeof(Dfn));
202
203 Build_G();
204 Tarjan(1,-1);
205 Clear_G();
206 for (int i=1;i<=n;i++)
207 for (int j=head[i];j!=-1;j=edge[j].next)
208 if (Belong[i]!=Belong[edge[j].to])
209 {
210 if (S.count(mp(Belong[i],Belong[edge[j].to]))==1) continue;
211 S.insert(mp(Belong[i],Belong[edge[j].to]));
212 S.insert(mp(Belong[edge[j].to],Belong[i]));
213 V.pb(mp(Belong[i],Belong[edge[j].to]));
214 V.pb(mp(Belong[edge[j].to],Belong[i]));
215 }
216
217
218 memset(head,-1,sizeof(head));cnt=0;
219 for (int i=0;i<V.size();i++) Add(V[i].fi,V[i].se);
220 father[1]=1;dep[1]=1;
221 memset(vis,false,sizeof(vis)),Dfs1(1);
222 memset(vis,false,sizeof(vis)),Dfs2(1,1);
223 Build(1,1,scc);
224 for (int i=Q;i>=1;i--)
225 {
226 int p=Belong[Op[i].u],q=Belong[Op[i].v];
227 if (Op[i].type==0)
228 {
229 if (p==q) continue;
230 int t=Lca(p,q);
231 if (t==p)
232 {
233 int k=0;
234 for (int j=head[t];j!=-1;j=edge[j].next)
235 if (Lca(edge[j].to,q)==edge[j].to && father[t]!=edge[j].to) {k=edge[j].to; break;}
236
237 Tree_Modify(q,k);
238 continue;
239 }
240
241 if (t==q)
242 {
243 int k=0;
244 for (int j=head[t];j!=-1;j=edge[j].next)
245 if (Lca(edge[j].to,p)==edge[j].to && father[t]!=edge[j].to) {k=edge[j].to; break;}
246 Tree_Modify(p,k);
247 continue;
248 }
249 int r,s;
250 for (int j=head[t];j!=-1;j=edge[j].next)
251 if (Lca(edge[j].to,p)==edge[j].to && father[t]!=edge[j].to) {r=edge[j].to; break;}
252 for (int j=head[t];j!=-1;j=edge[j].next)
253 if (Lca(edge[j].to,q)==edge[j].to && father[t]!=edge[j].to) {s=edge[j].to; break;}
254 Tree_Modify(p,r),Tree_Modify(q,s);
255 } else
256 if (Op[i].type==1)
257 {
258 if (p==q) {Ans[i]=0; continue;}
259 int t=Lca(p,q);
260 if (t==p)
261 {
262 int k=0;
263 for (int j=head[t];j!=-1;j=edge[j].next)
264 if (Lca(edge[j].to,q)==edge[j].to && father[t]!=edge[j].to) {k=edge[j].to; break;}
265 Ans[i]=Tree_Query(q,k);
266 continue;
267 }
268 if (t==q)
269 {
270 int k=0;
271 for (int j=head[t];j!=-1;j=edge[j].next)
272 if (Lca(edge[j].to,p)==edge[j].to && father[t]!=edge[j].to) {k=edge[j].to; break;}
273 Ans[i]=Tree_Query(p,k);
274 continue;
275 }
276
277 int r,s;
278 for (int j=head[t];j!=-1;j=edge[j].next)
279 if (Lca(edge[j].to,p)==edge[j].to && father[t]!=edge[j].to) {r=edge[j].to; break;}
280 for (int j=head[t];j!=-1;j=edge[j].next)
281 if (Lca(edge[j].to,q)==edge[j].to && father[t]!=edge[j].to) {s=edge[j].to; break;}
282 Ans[i]=Tree_Query(p,r)+Tree_Query(q,s);
283 }
284 }
285 for (int i=1;i<=Q;i++)
286 if (Op[i].type==1) Put_Int(Ans[i]);
287 return 0;
288 }
289
290
傻逼树剖280+系列
时间： 2024-08-06 07:49:44