제출 #714282

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
714282		vjudge1	Event Hopping (BOI22_events)	C++17	0 / 100	1563 ms	8628 KiB

events

#include <bits/stdc++.h>
#define ll long long
#define endl '\n'
using namespace std;
const int MAX = 3e5 + 5;
vector<int> adj[100001];
int color[100001], dis[100001];
void bfs(int s){
    queue<int> q;
    q.push(s);
    dis[s] = 0;
    color[s] = 1;
    while(!q.empty()){
        int u = q.front();
        q.pop();
        for(auto v : adj[u]){
            if(color[v]) continue;
            color[v] = 1;
            dis[v] = dis[u] + 1;
            q.push(v);
        }
    }
}
struct event{
    int s, e, i;
    bool operator<(event other){
        if(e == other.e){
            return s < other.s;
        }
        return e < other.e;
    }
};
int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int n, q;
    cin>>n>>q;
    vector<int> S(n + 1), E(n + 1);
    vector<event> arr;
    for (int i = 1; i <= n; i++)
    {
        cin>>S[i]>>E[i];
        arr.push_back({S[i], E[i], i});
    }
    sort(arr.begin(), arr.end());
    for(int i = 0; i < n - 1; i++){
        int first = arr[i].i;
        int second = arr[i + 1].i;
        if(S[second] <= E[first] && E[first] <= E[second]) adj[first].push_back(second);
    }
    while(q--){
        memset(color, 0, sizeof(color));
        memset(dis, -1, sizeof(dis));
        int s, e;
        cin>>s>>e;
        bfs(s);
        if(dis[e] != -1) cout<<dis[e]<<endl;
        else cout<<"impossible\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