Submission #1093084

#	Time	Username	Problem	Language	Result	Execution time	Memory
1093084		De3b0o	Event Hopping (BOI22_events)	C++17	0 / 100	163 ms	29008 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];
map<ll,pll> mx;
vector<ll> adj[N];
vector<pll> v;
bool vis[N];
ll idx[N];
ll g[N];
ll c;
map<ll,vector<ll>> mp;

void dfs(ll x , ll id)
{
    if(vis[x])
        return;
    vis[x]=1;
    idx[x]=id;
    g[x]=c;
    ll ne = -1;
    if(mx[r[x]].F>r[x])
        ne=mx[r[x]].S;
    if(mp[r[x]].size()==2)
    {
        if(mp[r[x]][0]==x)
            ne=mp[r[x]][1];
        else
            ne=mp[r[x]][0];
    }
    if(ne!=-1)
        dfs(ne,id+1);
}

int main()
{
    d3
    cin >> n >> q;
    for(int i = 1 ; n>=i ; i++)
    {
        cin >> l[i] >> r[i];
        if(mx[l[i]].F<r[i])
            mx[l[i]]={r[i],i};
        mx[r[i]]={0,0};
        v.pb({r[i],i});
        mp[r[i]].pb(i);
    }
    ll pmx = 0;
    ll pidx = 0;
    for(auto it : mx)
    {
        if(it.S.F<pmx)
        {
            mx[it.F]={pmx,pidx};
        }
        else
        {
            pmx=it.S.F;
            pidx=it.S.S;
        }
    }
    sort(v.begin(),v.end());
    for(auto it : v)
    {
        if(vis[it.S])
            continue;
        dfs(it.S,0);
        c++;
    }
    while(q--)
    {
        ll s , e;
        cin >> s >> e;
        if(s==e)
        {
            cout << 0 << "\n";
            continue;
        }
        if(r[s]==r[e])
        {
            cout << 1 << "\n";
            continue;
        }
        if(g[s]!=g[e]||idx[s]>idx[e])
        {
            cout << "impossible\n";
            continue;
        }
        cout << idx[e]-idx[s] << "\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