[51nod1213]二维曼哈顿距离最小生成树

时间:2023-02-17 23:06:01

  二维平面上有N个坐标为整数的点,点x1 y1同点x2 y2之间的距离为:横纵坐标的差的绝对值之和,即:Abs(x1 - x2) + Abs(y1 - y2)(也称曼哈顿距离)。求这N个点所组成的完全图的最小生成树的边权之和。
 Input
  第1行:1个数N,表示点的数量。(2 <= N <= 50000)
  第2 - N + 1行:每行2个数,表示点的坐标(0 <= x, y <= 1000000)
 Output
  输出N个点所组成的完全图的最小生成树的边权之和。

就当是攒新板子了。。

题解:http://blog.csdn.net/acm_cxlove/article/details/8890003

 #include<cstdio>
#include<iostream>
#include<cstring>
#include<algorithm>
#include<queue>
#include<cmath>
#include<cstdlib>
#define ll long long
#define ull unsigned long long
#define ui unsigned int
//#define d double
#define ld long double
const int maxn=,inf=;
struct zs{int x,y,v,id;}a[maxn],aa[maxn],e[maxn<<];int ne;
struct zs1{int v,id;}t[maxn],b[maxn];
int fa[maxn];
int i,j,k,n,m;
ll ans; int ra,fh;char rx;
inline int read(){
rx=getchar(),ra=,fh=;
while(rx<''&&rx!='-')rx=getchar();
if(rx=='-')fh=-,rx=getchar();
while(rx>='')ra=ra*+rx-,rx=getchar();return ra*fh;
} inline int abs(int x){return x<?-x:x;}
inline int getdis(int a,int b){
return abs(aa[a].x-aa[b].x)+abs(aa[a].y-aa[b].y);
}
inline void insert(int a,int b){
/*e[++tot].too=b,e[tot].pre=last[a],last[a]=tot,
e[++tot].too=a,e[tot].pre=last[b],last[b]=tot,
e[tot-1].dis=e[tot].dis=getdis(a,b);*/
e[++ne]=(zs){a,b,getdis(a,b)};
} bool operator <(zs a,zs b){return a.x<b.x||(a.x==b.x&&a.y<b.y);}
bool operator <(zs1 a,zs1 b){return a.v<b.v;}
bool cmpe(zs a,zs b){return a.v<b.v;} inline void mins(zs1 &a,zs1 b){if(b.v<a.v)a=b;}
inline void add(int x,zs1 mn){while(x<=n)mins(t[x],mn),x+=x&-x;}
inline int query(int x){zs1 mn=(zs1){inf,-};while(x)mins(mn,t[x]),x-=x&-x;return mn.id;}
inline void run(){
int i,cnt=;
for(i=;i<=n;i++)t[i]=(zs1){inf,-};
for(i=;i<=n;i++)b[i]=(zs1){a[i].y-a[i].x,i};
std::sort(b+,b++n);
for(i=;i<=n;a[b[i].id].v=n-cnt+,i++)cnt+=b[i].v!=b[i-].v||i==;
std::sort(a+,a++n);
for(i=n;i;i--){
int id=query(a[i].v);
if(id>)insert(a[i].id,id);
add(a[i].v,(zs1){a[i].x+a[i].y,a[i].id});
}
} inline int getfa(int x){return fa[x]!=x?fa[x]=getfa(fa[x]):x;}
int main(){
n=read();
for(i=;i<=n;i++)aa[i].x=read(),aa[i].y=read(); for(i=;i<=n;i++)a[i].x=aa[i].x,a[i].y=aa[i].y,a[i].id=i;
run(); for(i=;i<=n;i++)a[i].x=aa[i].x,a[i].y=-aa[i].y,a[i].id=i;
run(); for(i=;i<=n;i++)a[i].x=aa[i].y,a[i].y=aa[i].x,a[i].id=i;
run(); for(i=;i<=n;i++)a[i].x=-aa[i].y,a[i].y=aa[i].x,a[i].id=i;
run(); std::sort(e+,e++ne,cmpe);
for(i=;i<=n;i++)fa[i]=i;
for(i=;i<=ne;i++)if(getfa(e[i].x)!=getfa(e[i].y))
fa[fa[e[i].x]]=fa[e[i].y],ans+=e[i].v;
printf("%lld\n",ans);
}