[bzoj1969] [Ahoi2005]LANE 航线规划

  1 #include<cstdio>
  2 #include<iostream>
  3 #include<cstring>
  4 #include<algorithm>
  5 #define ui unsigned int
  6 using namespace std;
  7 const int maxn=30023,maxm=100023;
  8 struct zs{int too,pre;}e[maxm<<1];int tot,last[maxn];
  9 bool iscut[maxm<<1];
 10 struct zs1{int x,y;}a[maxm];
 11 struct zs2{bool del;int id,x,y;}b[40023];
 12 int fa[maxn],bel[maxn],dep[maxn],dfn[maxn],low[maxn],tim,L[maxn],R[maxn],TIM,sz[maxn],cha[maxn],id[maxn];
 13 int la[maxn<<1],pre[maxn<<1],too[maxn<<1],tt;
 14 int An[40023];
 15 int i,j,k,n,m,q,cnt;
 16 bool gg[maxm];
 17  
 18 int ra,fh;char rx;
 19 inline int read(){
 20     rx=getchar(),ra=0,fh=1;
 21     while((rx<‘0‘||rx>‘9‘)&&rx!=‘-‘)rx=getchar();
 22     if(rx==‘-‘)fh=-1,rx=getchar();
 23     while(rx>=‘0‘&&rx<=‘9‘)ra*=10,ra+=rx-48,rx=getchar();return ra*fh;
 24 }
 25  
 26 inline int getbel(int x){return bel[x]!=x?bel[x]=getbel(bel[x]):x;}
 27  
 28 void dfs(int x,int efa){
 29     dfn[x]=low[x]=++tim;
 30     for(int i=last[x];i;i=e[i].pre)if(i!=efa)
 31         if(!dfn[e[i].too])
 32             dfs(e[i].too,i^1),low[x]=min(low[x],low[e[i].too]);
 33         else low[x]=min(low[x],dfn[e[i].too]);
 34     if(dfn[x]==low[x]&&efa)iscut[efa]=iscut[efa^1]=1;
 35 }
 36 void dfs2(int x){
 37     dep[x]=dep[fa[x]]+1,sz[x]=1;
 38     for(int i=la[x];i;i=pre[i])
 39         if(too[i]!=fa[x])fa[too[i]]=x,dfs2(too[i]),sz[x]+=sz[too[i]];
 40 }
 41 void dfs3(int x,int chain){
 42     cha[x]=chain,L[x]=++TIM;
 43     int i,mx=0;
 44     for(i=la[x];i;i=pre[i])if(too[i]!=fa[x]&&sz[too[i]]>sz[mx])mx=too[i];
 45     if(!mx){R[x]=TIM;return;}
 46     dfs3(mx,chain);
 47     for(i=la[x];i;i=pre[i])if(too[i]!=fa[x]&&too[i]!=mx)dfs3(too[i],too[i]);
 48     R[x]=TIM;
 49 }
 50 inline int getlca(int a,int b){
 51     while(cha[a]!=cha[b]){
 52         if(dep[cha[a]]<dep[cha[b]])swap(a,b);
 53         a=fa[cha[a]];
 54     }
 55     return dep[a]<dep[b]?a:b;
 56 }
 57 inline void insert(int a,int b){
 58     e[++tot].too=b,e[tot].pre=last[a],last[a]=tot,
 59     e[++tot].too=a,e[tot].pre=last[b],last[b]=tot;
 60 }
 61 inline void ins(int a,int b){//printf(" %d-->%d\n",a,b);
 62     too[++tt]=b,pre[tt]=la[a],la[a]=tt,
 63     too[++tt]=a,pre[tt]=la[b],la[b]=tt;
 64 }
 65 int t[maxn];
 66 inline void add(int l,int r,int v){//printf("       add:  %d--%d  v:%d\n",l,r,v);
 67     while(l<=cnt)t[l]-=v,l+=l&-l;
 68     r++;while(r<=cnt)t[r]+=v,r+=r&-r;
 69 }
 70 inline int ask(int x){/*printf("__x:  %d\n",x);*/int sm=0;while(x)sm+=t[x],x-=x&-x;return sm;}
 71  
 72 inline int query(int x,int y){
 73     int lca=getlca(x,y);//printf("query:  %d %d  lca:%d   %d %d\n",x,y,lca,getbel(x),getbel(y));
 74     x=dep[x]+ask(L[x]),y=dep[y]+ask(L[y]),lca=dep[lca]+ask(L[lca]);//printf("dep:   %d %d %d\n",x,y,lca);
 75     return x+y-(lca<<1);
 76 }
 77 inline void link(int x,int y){//printf("link:%d   %d\n",x,y);
 78     int i,j,tmp;
 79     i=getbel(x),j=getbel(y);//printf("    %d %d   dep:%d %d\n",i,j,dep[i],dep[j]);
 80     while(i!=j){
 81         if(dep[i]<dep[j])swap(i,j);
 82         tmp=getbel(fa[i]);
 83         add(L[i],R[i],1/*dep[i]-dep[tmp]*/);//printf("i:%d   tmp:%d\n",i,tmp);
 84         bel[i]=tmp,i=bel[i];
 85     }
 86 }
 87  
 88  
 89 bool cmp(zs1 a,zs1 b){return a.x<b.x||(a.x==b.x&&a.y<b.y);}
 90 inline int getpos(int x,int y){
 91     int l=1,r=m,mid;
 92     while(l<r)
 93         if(a[(mid=l+r>>1)].x==x?(a[mid].y==y?gg[mid]:a[mid].y<y):a[mid].x<x)l=mid+1;else r=mid;
 94     return l;
 95 }
 96 int main(){
 97     n=read(),m=read();register int i;
 98     for(i=1;i<=m;i++){
 99         j=read(),k=read();
100         if(j>k)swap(j,k);
101         a[i].x=j,a[i].y=k;
102     }
103     sort(a+1,a+1+m,cmp);
104     int id1;i=0;
105     for(id1=read();id1!=-1;id1=read()){
106         i++,j=b[i].x=read(),k=b[i].y=read();
107         if(j>k)swap(j,k);
108         if(!id1)b[i].del=1,gg[b[i].id=getpos(j,k)]=1;
109     }q=i;
110      
111     tot=1;
112     for(i=1;i<=m;i++)if(!gg[i])insert(a[i].x,a[i].y);
113     dfs(1,0);
114     for(i=1;i<=n;i++)bel[i]=i;
115     for(i=2;i<=tot;i+=2)if(!iscut[i])
116         bel[getbel(e[i].too)]=getbel(e[i^1].too);
117     for(i=1;i<=n;i++)if(getbel(i)==i)id[i]=++cnt;
118     for(i=1;i<=q;i++){
119         if(b[i].del)a[b[i].id].x=id[bel[a[b[i].id].x]],a[b[i].id].y=id[bel[a[b[i].id].y]];
120         b[i].x=id[getbel(b[i].x)],b[i].y=id[getbel(b[i].y)];
121     }
122     for(i=2;i<=tot;i+=2)if(iscut[i])ins(id[bel[e[i].too]],id[bel[e[i^1].too]]);
123     for(i=1;i<=cnt;i++)bel[i]=i;
124     fa[1]=0,dfs2(1),dfs3(1,1);
125 //    for(i=1;i<=cnt;i++)printf("    i:%d   dfn:%d   bel:%d   L:%d  R:%d   dep:%d\n",i,L[i],cha[i],L[i],R[i],dep[i]);
126      
127     for(i=q;i;i--)//{
128         if(!b[i].del)An[i]=query(b[i].x,b[i].y);
129         else link(a[b[i].id].x,a[b[i].id].y);
130 //      for(j=1;j<=n;j++)printf("   %d",ask(j));puts("");
131 //  }
132     for(i=1;i<=q;i++)if(!b[i].del)printf("%d\n",An[i]);
133 }
134