Submission #417605

#	Time	Username	Problem	Language	Result	Execution time	Memory
417605		jamezzz	Event Hopping 2 (JOI21_event2)	C++17	100 / 100	243 ms	18456 KiB

event2

#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#include <ext/rope>
using namespace __gnu_cxx;

typedef tree<long long, null_type, less<long long>,
rb_tree_tag, tree_order_statistics_node_update> pbds;
//less_equal for identical elements

#define DEBUG

#ifdef DEBUG
#define debug(...) printf(__VA_ARGS__);
#else
#define debug(...)
#endif
#define sf scanf
#define pf printf
#define fi first
#define se second
#define pb emplace_back
#define sz(x) (int)x.size()
#define mnto(x,y) x=min(x,(__typeof__(x))y)
#define mxto(x,y) x=max(x,(__typeof__(x))y)
#define INF 1023456789
#define LINF 1023456789123456789
#define all(x) x.begin(), x.end()
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef pair<ll, ll> pll;
typedef tuple<int, int, int> iii;
typedef tuple<int, int, int, int> iiii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<pll> vll;

struct range{ int l,r,i; };
vector<range> sl;

int n,k,p[100005][20];
ii sfx[100005];
vi ans;
vii a;
set<ii> s;

int num(int l,int r){ //counts number of things in this range
	int lo=0,hi=n-1,mid,res=-1;
	while(lo<=hi){
		mid=(lo+hi)/2;
		if(l<=sl[mid].l)res=mid,hi=mid-1;
		else lo=mid+1;
	}
	if(res==-1)return 0;
	int st=sfx[res].se;
	if(sfx[res].fi>r)return 0;
	int ans=1;
	for(int k=19;k>=0;--k){
		if(p[st][k]!=-1&&a[p[st][k]].se<=r){
			ans+=(1<<k);
			st=p[st][k];
		}
	}
	return ans;
}

int main(){
	sf("%d%d",&n,&k);
	for(int i=0;i<n;++i){
		int l,r;sf("%d%d",&l,&r);
		a.pb(l,r);
		sl.push_back({l,r,i});
	}
	sort(all(sl),[&](range &a,range &b){return a.l<b.l;});
	sfx[n]=ii(INF,-1);
	for(int i=n-1;i>=0;--i){
		sfx[i]=min(sfx[i+1],ii(sl[i].r,sl[i].i));
	}
	for(int i=0;i<n;++i){
		int lo=0,hi=n-1,mid,res=-1;
		while(lo<=hi){
			mid=(lo+hi)/2;
			if(a[i].se<=sl[mid].l)res=mid,hi=mid-1;
			else lo=mid+1;
		}
		if(res==-1)p[i][0]=-1;
		else p[i][0]=sfx[res].se;
	}
	for(int k=1;k<20;++k){
		for(int i=0;i<n;++i){
			if(p[i][k-1]!=-1)p[i][k]=p[p[i][k-1]][k-1];
			else p[i][k]=-1;
		}
	}
	int tot=num(0,1e9);
	if(tot<k)pf("-1\n"),exit(0);
	s.insert({0,1e9});
	for(int i=0;i<n;++i){
		auto it=s.upper_bound({a[i].fi,INF});
		if(it==s.begin())continue;
		else --it;
		int l,r;tie(l,r)=*it;
		if(r<a[i].se)continue;
		int nw=tot-num(l,r)+num(l,a[i].fi)+num(a[i].se,r)+1;
		if(nw>=k){
			tot=nw;
			s.erase(it);
			s.insert({l,a[i].fi});
			s.insert({a[i].se,r});
			ans.pb(i);
		}
	}
	if(sz(ans)<k)pf("-1\n");
	else{
		for(int i=0;i<k;++i)pf("%d\n",ans[i]+1);
	}
}

Compilation message (stderr)

event2.cpp: In function 'int main()':
event2.cpp:71:4: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   71 |  sf("%d%d",&n,&k);
      |    ^
event2.cpp:73:13: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   73 |   int l,r;sf("%d%d",&l,&r);
      |             ^

• Subtask 1: 7 / 7
• Subtask 2: 1 / 1
• Subtask 3: 31 / 31
• Subtask 4: 61 / 61