Submission #416665

#	Time	Username	Problem	Language	Result	Execution time	Memory
416665		REALITYNB	Autobahn (COI21_autobahn)	C++14	20 / 100	2 ms	540 KiB

autobahn

#include <bits/stdc++.h> 
#define int long long 
#define inf 1e12
#define all(a) a.begin(),a.end()
using namespace std; 
signed main(){
	ios_base::sync_with_stdio(0);
	cin.tie(nullptr);
	int n,k,x ; 
	cin>>n>>k>>x;
	vector<int> l(n) ,t(n) , r(n) , events ; 
	for(int i=0;i<n;i++){
		cin>>l[i]>>t[i]>>r[i] ; 
		int le = l[i],re=r[i],rr  = l[i]+t[i]-1 ; 
		events.push_back(le); 
		events.push_back(re);
		events.push_back(rr); 
		events.push_back(re+1) ; 
		events.push_back(rr+1) ; 
		events.push_back(re-x+1) ; 
		events.push_back(rr-x+1) ; 
		events.push_back(le-x+1); 
		events.push_back(re-x) ; 
		events.push_back(rr-x) ; 

	}
	events.push_back(inf) ; 
	sort(all(events)) ; 
	auto it = unique(all(events),[&](int a ,int b){return a==b;}) ; 
	events.resize(distance(events.begin(),it)) ; 
	vector<int> illegals(events.size()) ; 
	vector<int> num(events.size()) ; 
	for(int i=0;i<n;i++){
		int j = lower_bound(all(events),l[i])-events.begin() ; 
		num[j]++ ; 
		int k = lower_bound(all(events),r[i]+1)-events.begin() ; 
		num[k]-- ; 
	}
	for(int i=0;i<n;i++){
		int le = l[i],re=r[i] ,rr=l[i]+t[i]-1 ; 
		if(rr<=re){
			int j = lower_bound(all(events),rr+1)-events.begin(); 
			illegals[j]++; 
			j = lower_bound(all(events),re+1)-events.begin() ; 
			illegals[j]--; 
		}
	}
	for(int i=1;i<events.size();i++) num[i]+=num[i-1],illegals[i]+=illegals[i-1] ; 
	int curl = events[0] , curr =-inf, val = 0 , j = 0 , ans = 0 ;  
/*	for(int i=0;i<events.size();i++){
		cout << "minute :" << events[i] << " " << num[i] << "  "<< illegals[i] << endl ; 
	}*/
int goal = 0 ; 
	for(int i=0;i+1<events.size();i++){
		curl=events[i] ; 
		if(curr<=curl){
			curr = curl ; 
			val =((int)(num[i]>=k))*illegals[i]; 
			j=i+1 ; 
		}
		else{
			val-=(events[i]-events[i-1])*(illegals[i-1])*((int)(num[i-1]>=k)) ; 
		}
		while(curr-curl+1<x){
			if(events[j]>x+curl-1){
				val+=(curl+x-1-curr)*(illegals[j-1])*((int)(num[j-1]>=k)) ; 
				curr = curl+x-1 ; 
				break ; 
			}
			++j; 
			val+=(min(events[j]-1,curl+x-1)-curr)*((int)(num[j-1]>=k))*illegals[j-1] ; 
			curr = min(events[j]-1,curl+x-1) ; 
		}

		if(val>ans){
			ans=val; 
			goal = events[i] ; 
		}
	//	cout <<events[i] << " " << val << " " << j << " " << curr << endl ; 
	}

	cout << ans  ; 
	
	return 0; 
}

Compilation message (stderr)

autobahn.cpp: In function 'int main()':
autobahn.cpp:40:7: warning: unused variable 'le' [-Wunused-variable]
   40 |   int le = l[i],re=r[i] ,rr=l[i]+t[i]-1 ;
      |       ^~
autobahn.cpp:48:15: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   48 |  for(int i=1;i<events.size();i++) num[i]+=num[i-1],illegals[i]+=illegals[i-1] ;
      |              ~^~~~~~~~~~~~~~
autobahn.cpp:54:17: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   54 |  for(int i=0;i+1<events.size();i++){
      |              ~~~^~~~~~~~~~~~~~
autobahn.cpp:53:5: warning: variable 'goal' set but not used [-Wunused-but-set-variable]
   53 | int goal = 0 ;
      |     ^~~~

• Subtask 1: 20 / 20
• Subtask 2: 0 / 30
• Subtask 3: 0 / 50