Submission #721809

#	Time	Username	Problem	Language	Result	Execution time	Memory
721809		Mr_Husanboy	Event Hopping (BOI22_events)	C++17	10 / 100	1586 ms	61416 KiB

events

#include<bits/stdc++.h>
using namespace std;
 
#define all(a) (a).begin(), (a).end()
template<typename T>
int len(T &a){
    return a.size();
}
using ll = long long;
const int inf = 1e9;
const ll infl = 1e18;
#define ff first
#define ss second

void solve(){
    int n, q; cin >> n >> q;
    vector<pair<int,int>> e(n);
   // map<int,int> mp;
    for(int i = 0; i < n; i ++){
        cin >> e[i].ff >> e[i].ss; 
        //mp[e[i].ff] = 1; mp[e[i].ss] = 1;
    }
    vector<vector<int>> g(n);
    for(int i = 0; i < n; i ++){
        for(int j = 0;j < n; j ++){
            if(i == j) continue;
            if(e[i].ss >= e[j].ff && e[i].ss <= e[j].ss){
                //cout << i + 1 << ' ' << j + 1 << endl;
                g[i].push_back(j);
            }
        }
    }
    if(n > 4000) assert(0);
    vector dis(n, vector(n, 1e9));
    auto bfs = [&](int i)->void{
        queue<int> q;
        vector<int> used(n);
        q.push(i);
        dis[i][i] = 0;
        used[i] = 1;
        while(!q.empty()){
            int t = q.front();
            q.pop();
            for(auto u : g[t]){
                if(used[u]) continue;
                used[u] = 1;
                dis[i][u] = dis[i][t] + 1;
                q.push(u);
            }
        }
    };
    vector<int> done(n);
    while(q --){
        int a, b; cin >> a >> b;
        a --; b --;
        if(!done[a]) bfs(a);
        if(dis[a][b] == inf){
            cout << "impossible\n";
        }else cout << dis[a][b] << '\n';
    }
}

int main(){
    ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
    int testcases = 1;
    //cin >> testcases;
    while(testcases --){
        solve();
        if(testcases) cout << '\n';
        #ifdef LOCAL
        else cout << '\n';
        cout << "__________________" << endl;
        #endif
    }
    return 0;
}

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