Submission #1093089

#	Time	Username	Problem	Language	Result	Execution time	Memory
1093089		De3b0o	Event Hopping (BOI22_events)	C++17	0 / 100	291 ms	406868 KiB

events

#include<bits/stdc++.h>
#include<random>
#define ll long long
#define F first
#define S second
#define in insert
#define pb push_back
#define ppb pop_back()
#define d3 ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define cans cout << ans << "\n";
#define yes cout << "Yes" << "\n";
#define no cout << "No" << "\n";
#define pll pair<ll,ll>
#define lin cout << "\n";
#define sqr 340
#define mod 1000000007
#define mid ((l+r)/2)
#define lc (2*x)
#define rc (2*x+1)

using namespace std;

const ll N = 100009;

ll n , q;
ll l[N] , r[N];
vector<ll> adj[N];
ll s , e;
bool vis[N];
ll sb[5009][5009];
ll ans;

void bfs(ll x , ll d , ll o)
{
    queue<pll> qu;
    qu.push({x,d});
    while(!qu.empty())
    {
        pll nd = qu.front();
        qu.pop();
        if(vis[nd.F])
            continue;
        vis[nd.F]=1;
        sb[o][nd.F]=nd.S;
        for(auto it : adj[nd.F])
            qu.push({it,nd.S+1});
    }
}

void bfs(ll x , ll d)
{
    queue<pll> qu;
    qu.push({x,d});
    while(!qu.empty())
    {
        pll nd = qu.front();
        qu.pop();
        if(vis[nd.F])
            continue;
        vis[nd.F]=1;
        if(nd.F==e)
            ans=nd.S;
        for(auto it : adj[nd.F])
            qu.push({it,nd.S+1});
    }
}

int main()
{
    d3
    cin >> n >> q;
    for(int i = 1 ; n>=i ; i++)
        for(int j = 1 ; n>=j ; j++)
            sb[i][j]=-1;
    for(int i = 1 ; n>=i ; i++)
        cin >> l[i] >> r[i];
    for(int i = 1 ; n>=i ; i++)
    {
        for(int j = 1 ; n>=j ; j++)
        {
            if(i==j)
                continue;
            if(r[i]>=l[j]&&r[i]<=r[j])
                adj[i].pb(j);
        }
    }
    if(n<=5000)
    {
        for(int i = 1 ; n>=i ; i++)
        {
            for(int j = 1 ; n>=j ; j++)
                vis[j]=0;
            bfs(i,0,i);
        }
    }
    while(q--)
    {
        cin >> s >> e;
        ans=-1;
        if(n<=5000)
            ans=sb[s][e];
        else
        {
            for(int i = 1 ; n>=i ; i++)
                vis[i]=0;
            bfs(s,0);
        }
        if(ans==-1)
            cout << "impossbile\n";
        else
            cans
    }
}

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