Submission #595575

#	Time	Username	Problem	Language	Result	Execution time	Memory
595575		Deepesson	Event Hopping (BOI22_events)	C++17	0 / 100	1580 ms	20632 KiB

events

#include <bits/stdc++.h>
#define MAX 200005
int N,Q;
typedef std::pair<int,int> pii;
std::vector<pii> eventos;

std::vector<int> add[MAX];

std::vector<int> rem[MAX];

int tab[MAX*4];

int query(int l,int r,int la=0,int ra=MAX-1,int pos=1){
    if(la>r||ra<l)return 1e9;
    if(la>=l&&ra<=r){
        return tab[pos];
    }
    int m = (la+ra)/2;
    return std::min(query(l,r,la,m,pos*2),query(l,r,m+1,ra,(pos*2)+1));
}

void update(int t,int k,int la=0,int ra=MAX-1,int pos=1){
    if(la>t||ra<t)return;
    if(la==ra){
        tab[pos]=k;
        return;
    }
    int m = (la+ra)/2;
    update(t,k,la,m,pos*2);
    update(t,k,m+1,ra,(pos*2)+1);
    tab[pos]=std::min(tab[pos*2],tab[(pos*2)+1]);
}

void zerar(void){for(auto&x:tab)x=1e9;}

typedef std::pair<int,int*> pipo;
int custos[MAX];
void simula(int x){
    zerar();
    for(auto&x:custos)x=1e9;
    update(eventos[x].second,0);
    for(int i=0;i!=MAX;++i){
        for(auto&x:rem[i]){
            int d = query(eventos[x].first,eventos[x].second);
            update(eventos[x].second,d+1);
            custos[x]=d;
        }
    }
    custos[x]=0;
}
int main()
{
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    std::cout.tie(0);
    std::cin>>N>>Q;
    for(int i=0;i!=N;++i){
        int a,b;
        std::cin>>a>>b;
        eventos.push_back({a,b});
    }

    {
        std::vector<pipo> comprime;
        for(auto&x:eventos){
            comprime.push_back({x.first,&x.first});
            comprime.push_back({x.second,&x.second});
        }
        std::sort(comprime.begin(),comprime.end());
        int last=-1,cord=1;
        for(auto&x:comprime){
            if(x.first!=last){
                last=x.first;
                ++cord;
            }
            *x.second=cord;
        }
    }
    for(int i=0;i!=N;++i){
        add[eventos[i].first].push_back(i);
        rem[eventos[i].second].push_back(i);
    }
    for(int i=0;i!=Q;++i){
        int a,b;
        std::cin>>a>>b;
        --a;--b;
        simula(a);
        int d = custos[b];
        if(d>=1e6){
            std::cout<<"impossible\n";
        }else {
            std::cout<<d<<"\n";
        }
    }
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 30