bzoj 1604: [Usaco2008 Open]Cow Neighborhoods 奶牛的邻居 曼哈顿生成树
大致题意:统计平面上由曼哈顿距离小于等于c的点对组成联通块的个数。
曼哈顿生成树的模板题。有关讲解:http://blog.csdn.net/acm_cxlove/article/details/8890003
#include<iostream> #include<cstdio> #include<algorithm> #include<cstring> using namespace std; #define MAXN 100100 #define MAXE MAXN*8 #define INF 0x3f3f3f3f #define INFL 0x3f3f3f3f3f3f3f3fLL typedef long long qword; int n,m; struct edge { int x,y; qword d; }e[MAXE]; int tope=-1; bool cmp_d(edge e1,edge e2) { return e1.d<e2.d; } int uf[MAXN]; int get_fa(int now) { return uf[now]==now ? now : uf[now]=get_fa(uf[now]); } int comb(int x,int y) { x=get_fa(x); y=get_fa(y); if (x==y)return false; uf[x]=y; return true; } struct point { qword x,y; int id; }pl[MAXN]; bool cmp_x(point p1,point p2) { if (p1.x==p2.x)return p1.y>p2.y; return p1.x>p2.x; } void rotate1() { for (int i=0;i<n;i++) pl[i].x=-pl[i].x; } void rotate2() { for (int i=0;i<n;i++) pl[i].y=-pl[i].y; } void rotate3() { for (int i=0;i<n;i++) swap(pl[i].x,pl[i].y); } qword h[MAXN],toph=-1; qword tarr[MAXN]; int tarr_id[MAXN]; void Add_tarr(int pos,qword v,int id) { while (pos<MAXN) { tarr[pos]=min(tarr[pos],v); if (v==tarr[pos])tarr_id[pos]=id; pos+=pos&(-pos); } } pair<qword,int> Qry_tarr(int pos) { pair<qword,int> ret; ret.first=INFL; while (pos) { ret.first=min(ret.first,tarr[pos]); if (ret.first==tarr[pos]) ret.second=tarr_id[pos]; pos-=pos&(-pos); } return ret; } void work() { int i,j; toph=0; memset(tarr,0x3f,sizeof(tarr)); for (i=0;i<n;i++) h[++toph]=pl[i].x-pl[i].y; sort(h+1,h+toph+1); toph=unique(h+1,h+toph+1)-h-1; sort(pl,pl+n,cmp_x); for (i=0;i<n;i++) { pair<qword,int> pr; qword t=pl[i].x-pl[i].y; t=lower_bound(h+1,h+toph+1,t)-h; pr=Qry_tarr(t); if (pr.first!=INFL) { e[++tope].x=pl[i].id; e[tope].y=pr.second; e[tope].d=pr.first-pl[i].x-pl[i].y; } Add_tarr(t,pl[i].x+pl[i].y,pl[i].id); } } int is_root[MAXN],uf_size[MAXN]; int main() { freopen("input.txt","r",stdin); //freopen("output.txt","w",stdout); int i,j,k,x,y,z; scanf("%d%d",&n,&m); for (i=0;i<n;i++) { scanf("%lld%lld",&pl[i].x,&pl[i].y); pl[i].id=i; } //1 work(); //2 rotate3(); work(); rotate3(); //3 rotate2(); rotate3(); work(); rotate3(); rotate2(); //4 rotate2(); work(); rotate2(); //5 rotate2(); rotate1(); work(); rotate1(); rotate2(); //6 rotate1(); rotate2(); rotate3(); work(); rotate3(); rotate2(); rotate1(); //7 rotate1(); rotate3(); work(); rotate3(); rotate1(); //8 rotate1(); work(); rotate1(); sort(e,e+tope+1,cmp_d); for (i=0;i<=n;i++)uf[i]=i; for (i=0;i<=tope && e[i].d<=m;i++) { comb(e[i].x,e[i].y); } int ans2=0; for (i=0;i<n;i++) { is_root[get_fa(i)]=1; uf_size[uf[i]]++; } for (i=1;i<n;i++) is_root[i]+=is_root[i-1]; for (i=0;i<n;i++) ans2=max(ans2,uf_size[i]); printf("%d %d\n",is_root[n-1],ans2); return 0; }
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