bzoj5017 炸弹 (线段树优化建图+tarjan+拓扑序dp)

直接建图边数太多，用线段树优化一下

然后缩点，记下来每个点里有多少个炸弹

然后按拓扑序反向dp一下就行了

 #include<bits/stdc++.h>
 #define pa pair<ll,int>
 #define CLR(a,x) memset(a,x,sizeof(a))
 using namespace std;
 typedef long long ll;
 const int maxn=5e5+,maxp=maxn*,maxl=maxn*,P=1e9+;
 const ll inf=1e18+;

 inline ll rd(){
     ll x=;char c=getchar();int neg=;
     while(c<''||c>''){if(c=='-') neg=-;c=getchar();}
     while(c>=''&&c<='') x=x*+c-'',c=getchar();
     return x*neg;
 }

 int N;
 ll pos[maxn],r[maxn];
 int rg[maxn][],id[maxn],ch[maxp][],pct,root;
 int eg[maxl][],egh[maxp],ect;
 int eg2[maxl][],egh2[maxp],ect2,ine[maxp];
 int dfn[maxp],low[maxp],tot,stk[maxp],sh;
 int bel[maxp],nct,hav[maxp],hh[maxp];
 int val[maxp],rk[maxp];
 bool instk[maxp],islef[maxp],to[maxp];
 queue<int> q;

 inline void adeg(int a,int b){
     eg[++ect][]=b;eg[ect][]=egh[a];egh[a]=ect;
 }
 inline void adeg2(int a,int b){
     ine[b]++;
     eg2[++ect2][]=b;eg2[ect2][]=egh2[a];egh2[a]=ect2;
 }

 void build(int &p,int l,int r){
     p=++pct;
     if(l==r) id[l]=p,islef[p]=;
     if(l<r){
         int m=l+r>>;
         build(ch[p][],l,m);
         build(ch[p][],m+,r);
         adeg(p,ch[p][]),adeg(p,ch[p][]);
     }
 }

 void conn(int p,int l,int r,int x,int y,int z){
     if(x>y) return;
     if(x<=l&&r<=y){
         adeg(z,p);
     }else{
         int m=l+r>>;
         if(x<=m) conn(ch[p][],l,m,x,y,z);
         if(y>=m+) conn(ch[p][],m+,r,x,y,z);
     }
 }

 void tarjan(int x){
     dfn[x]=low[x]=++tot;
     stk[++sh]=x;instk[x]=;
     for(int i=egh[x];i;i=eg[i][]){
         int b=eg[i][];
         if(instk[b]) low[x]=min(low[x],dfn[b]);
         else if(!dfn[b]){
             tarjan(b);
             low[x]=min(low[x],low[b]);
         }
     }
     if(dfn[x]==low[x]){
         ++nct;
         while(sh){
             bel[stk[sh]]=nct;
             hav[stk[sh]]=hh[nct],hh[nct]=stk[sh];
             val[nct]+=islef[stk[sh]];
             instk[stk[sh]]=;
             sh--;
             if(stk[sh+]==x) break;
         }
     }
 }

 int main(){
     //freopen(".in","r",stdin);
     int i,j,k;
     N=rd();
     for(i=;i<=N;i++) pos[i]=rd(),r[i]=rd();
     for(i=;i<=N;i++){
         rg[i][]=lower_bound(pos+,pos+N+,pos[i]-r[i])-pos;
         rg[i][]=upper_bound(pos+,pos+N+,pos[i]+r[i])-pos-;
         // printf("%d %d %d\n",i,rg[i][0],rg[i][1]);
     }
     build(root,,N);
     for(i=;i<=N;i++){
         conn(root,,N,rg[i][],i-,id[i]);
         conn(root,,N,i+,rg[i][],id[i]);
     }
     for(i=;i<=pct;i++){
         if(!dfn[i]) tarjan(i);
     }
     for(i=;i<=nct;i++){
         for(j=hh[i];j;j=hav[j]){
             for(k=egh[j];k;k=eg[k][]){
                 int bb=bel[eg[k][]];if(bb==i) continue;
                 if(!to[bb]) adeg2(i,bb),to[bb]=;
             }
         }

         for(j=hh[i];j;j=hav[j]){
             for(k=egh[j];k;k=eg[k][]){
                 int bb=bel[eg[k][]];
                 to[bb]=;
             }
         }
     }
     int nn=;
     for(i=;i<=nct;i++){
         if(!ine[i]) q.push(i);
     }
     while(!q.empty()){
         int p=q.front();q.pop();
         rk[++nn]=p;
         for(i=egh2[p];i;i=eg2[i][]){
             int b=eg2[i][];
             if(--ine[b]==) q.push(b);
         }

     }
     for(i=nct;i;i--){
         int p=rk[i];
         for(j=egh2[p];j;j=eg2[j][]){
             int b=eg2[j][];
             val[p]+=val[b];
         }
     }
     ll ans=;
     for(i=;i<=N;i++){
         ans=(ans+1ll*i*val[bel[id[i]]])%P;
     }
     printf("%lld\n",ans);
     return ;
 }