BZOJ2225: [Spoj 2371]Another Longest Increasing CDQ分治，3维LIS

Code:

#include <cstdio>
#include <algorithm>
#include <cstring>
#define maxn 200000
#define setIO(s) freopen(s".in","r",stdin)
using namespace std;
int n,ans[maxn],hh[maxn];
inline void getmax(int &a,int b){ if(b>a)a=b; }
struct Node{
    int x,y,z,org;
}node[maxn];
int cmpx(Node a,Node b)
{
    if(a.x==b.x&&a.y==b.y) return a.z<b.z;
    else if(a.x==b.x) return a.y<b.y;
    else return a.x<b.x;
}
int cmpy(Node a,Node b){
    if(a.y==b.y) return a.z<b.z;
    else return a.y<b.y;
}
struct BIT{
    int C[maxn];
    int lowbit(int t) { return t&(-t);}
    void update(int p,int x){ while(p<maxn) getmax(C[p],x),p+=lowbit(p); }
    int query(int p){
        if(p<=0) return 0;
        int ss=0;
        while(p>0) getmax(ss,C[p]),p-=lowbit(p);
        return ss;
    }
    void del(int p){ while(p<maxn)C[p]=0,p+=lowbit(p); }
}tree;
void solve(int l,int r){
    if(l>=r) return;
    int mid=(l+r)>>1,tl=l,tr=mid+1;
    solve(l,mid);
    sort(node+l,node+mid+1,cmpy),sort(node+mid+1,node+r+1,cmpy);

    while(tl<=mid&&tr<=r) {
        if(node[tl].y<node[tr].y) {
            tree.update(node[tl].z,ans[node[tl].org]);
            ++tl;
        }
        else {
            getmax(ans[node[tr].org],tree.query(node[tr].z-1)+1);
            ++tr;
        }
    }
    for(int i=tr;i<=r;++i) getmax(ans[node[i].org],tree.query(node[i].z-1)+1);
    for(int i=l;i<=mid;++i) tree.del(node[i].z);
    sort(node+mid+1,node+1+r,cmpx),solve(mid+1,r);
}

int main(){
    //setIO("input");
    scanf("%d",&n);
    for(int i=1;i<=n;++i) node[i].x=node[i].org=i,scanf("%d%d",&node[i].y,&node[i].z),hh[i]=node[i].z;
    sort(hh+1,hh+1+n);
    for(int i=1;i<=n;++i) node[i].z=lower_bound(hh+1,hh+1+n,node[i].z)-hh;
    for(int i=1;i<=n;++i) ans[i]=1;
    sort(node+1,node+1+n,cmpx);
    solve(1,n);
    int h=0;
    for(int i=1;i<=n;++i) getmax(h,ans[i]);
    printf("%d",h);
    return 0;
}