【bzoj1178】 Apio2009—CONVENTION会议中心

#include<algorithm>
#include<iostream>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<cmath>
#include<set>
#define LL long long
#define inf 2147483640
#define Pi acos(-1.0)
#define free(a) freopen(a".in","r",stdin),freopen(a".out","w",stdout);
using namespace std;

const int maxn=200010;
struct data {
	int l,r;
	friend bool operator < (const data &x,const data &y) {
		return x.r==y.r ? x.l>y.l : x.r<y.r;
	}
}a[maxn],t[maxn];
int X[maxn],Y[maxn],next[maxn][30],L[maxn],R[maxn],n,m;

int cal(int l,int r) {
	int x=lower_bound(X+1,X+1+m,l)-X;
	if (Y[x]>r || x>m) return 0;
	int res=1;
	for (int i=20;i>=0;i--) if (next[x][i] && Y[next[x][i]]<=r) res+=1<<i,x=next[x][i];
	return res;
}
int main() {
	scanf("%d",&n);
	for (int i=1;i<=n;i++) scanf("%d%d",&t[i].l,&t[i].r),a[i]=t[i];
	sort(t+1,t+1+n);
	m=0;
	for (int i=1;i<=n;i++) if (m==0 || t[i].l>t[m].l) t[++m]=t[i];
	for (int i=1;i<=m;i++) X[i]=t[i].l,Y[i]=t[i].r;
	for (int i=1,j=1;i<=m;i++) {
		while (j<=m && t[j].l<=t[i].r) j++;
		if (j<=m) next[i][0]=j;
	}
	for (int j=1;j<=20;j++)
		for (int i=1;i<=m;i++) next[i][j]=next[next[i][j-1]][j-1];
	int ans;
	printf("%d\n",ans=cal(-inf,inf));
	set<data> s;
	s.insert((data){inf,inf});
	s.insert((data){-inf,-inf});
	int cnt=0;
	for (int i=1;i<=n;i++) {
		set<data>::iterator x=s.lower_bound(a[i]),y=x;y--;
		int l1=y->r,r1=a[i].l,l2=a[i].r,r2=x->l;
		if (l1>=r1 || l2>=r2) continue;
		if (cal(l1+1,r2-1)==cal(l1+1,r1-1)+cal(l2+1,r2-1)+1) {
			if (++cnt==ans) printf("%d",i);
			else printf("%d ",i);
			s.insert(a[i]);
		}
	}
	return 0;
}