UVAlive3662 Another Minimum Spanning Tree 莫队算法

就是莫队的模板题

/*
Memory: 0 KB        Time: 1663 MS
Language: C++11 4.8.2        Result: Accepted
*/
 
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<iostream>
#include<cstdlib>
#include<cmath>
using namespace std;
typedef long long LL;
const int INF=0x3f3f3f3f;
const int maxn=;
struct Point
{
    int x,y,id;
    bool operator<(const Point &e)const
    {
        if(x==e.x)return y<e.y;
        return x<e.x;
    }
} point[maxn];
struct Edge
{
    int u,v,w;
    bool operator<(const Edge &e)const
    {
        return w<e.w;
    }
} edge[maxn*];
int tot;
void addedge(int u,int v,int w)
{
    ++tot;
    edge[tot].u=u;
    edge[tot].v=v;
    edge[tot].w=w;
}
struct Node
{
    int minval,pos;
    void init()
    {
        minval=INF;
        pos=-;
    }
} node[maxn];
int lowbit(int x)
{
    return x&(-x);
}
void update(int i,int val,int pos)
{
    while(i>)
    {
        if(val<node[i].minval)
        {
            node[i].minval=val;
            node[i].pos=pos;
        }
        i-=lowbit(i);
    }
}
int query(int i,int m)
{
    int minval=INF,pos=-;
    while(i<=m)
    {
        if(node[i].minval<minval)
        {
            minval=node[i].minval;
            pos=node[i].pos;
        }
        i+=lowbit(i);
    }
    return pos;
}
int dis(Point a,Point b)
{
    return abs(a.x-b.x)+abs(a.y-b.y);
}
int c[maxn],b[maxn],n;
void build()
{
    sort(point+,point+n+);
    for(int i=; i<=n; ++i)
        b[i]=c[i]=point[i].y-point[i].x;
    sort(c+,c++n);
    int m=unique(c+,c++n)-(c+);
    for(int i=; i<=m; ++i)
        node[i].init();
    for(int i=n; i>; --i)
    {
        int pos=lower_bound(c+,c++m,b[i])-c;
        int tt=query(pos,m);
        if(tt!=-)addedge(point[i].id,point[tt].id,dis(point[i],point[tt]));
        update(pos,point[i].x+point[i].y,i);
    }
}
int fa[maxn];
int find(int x)
{
    if(x==fa[x])return x;
    return fa[x]=find(fa[x]);
}
LL solve()
{
    sort(edge+,edge++tot);
    for(int i=; i<=n; ++i)
        fa[i]=i;
    int cnt=;
    LL mst=;
    for(int i=; i<=tot; ++i)
    {
        int fx=find(edge[i].u);
        int fy=find(edge[i].v);
        if(fx==fy)continue;
        fa[fy]=fx;
        mst+=edge[i].w;
        cnt++;
        if(cnt>=n)break;
    }
    return mst;
}
int main()
{
 
    int cas=;
    while(~scanf("%d",&n),n)
    {
        tot=;
        for(int i=; i<=n; ++i)
            scanf("%d%d",&point[i].x,&point[i].y),point[i].id=i;
        build();
        for(int i=; i<=n; ++i)
            point[i].y=-point[i].y;
        build();
        for(int i=; i<=n; ++i)
            point[i].y=-point[i].y,swap(point[i].x,point[i].y);
        build();
        for(int i=; i<=n; ++i)
            point[i].y=-point[i].y;
        build();
        printf("Case %d: Total Weight = %lld\n",++cas,solve());
    }
    return ;
}