Submission #670325

#	Time	Username	Problem	Language	Result	Execution time	Memory
670325		efedmrlr	Event Hopping (BOI22_events)	C++17	10 / 100	208 ms	11500 KiB

events

#include <bits/stdc++.h>
#define int long long int
#define MP make_pair
#define pb push_back

using namespace std;

const int N = 1e3+5;
const int Q = 105;
const int MOD = 1e9+7;

int n,m,q;
vector<pair<int,int> > events;
vector<int> adj[N];
vector<pair<int,int> > queries(Q);
bool vis[N];
int bfs(int x, int y) {
    queue<int> nodes;
    nodes.push(x);
    nodes.push(-1);
    for (int i = 1; i <= n; i++)
    {
        vis[i] = false;
    }
    int dist = 0;
    int cur;
    while (nodes.size() > 1) {
        cur = nodes.front();
        nodes.pop();
        if(cur==-1) {
            dist++;
            nodes.push(-1);
            continue;
        }
        if(cur == y) {
            return dist;
        }
        if(vis[cur]) continue;
        vis[cur] = true;
        for (int i = 0; i < adj[cur].size(); i++)
        {
            if(vis[adj[cur][i]]) continue;
            nodes.push(adj[cur][i]);
        }
        
    }
    return -1;
}

void solve() {
    cin>>n>>q;
    events.pb(MP(-1,-1));
    for (int i = 1; i <= n; i++)
    {
        int tmp1,tmp2;
        cin>>tmp1>>tmp2;
        events.pb(MP(tmp1,tmp2));

    }
    for (int i = 0; i < q; i++)
    {
        cin>>queries[i].first>>queries[i].second;
    }
    
    for (int i = 1; i <= n; i++)
    {
        for (int j = i+1; j <= n; j++)
        {

            if(events[i].second > events[j].second &&
                 events[j].second >= events[i].first) {
                adj[j].pb(i);
                //cout<<j<<" >> "<<i<<"\n";
            }
            else if(events[j].second > events[i].second &&
                     events[i].second >= events[j].first) {
                adj[i].pb(j);
                //cout<<i<<" >> "<<j<<"\n";
            }
            else if(events[j].second == events[i].second) {
                adj[i].pb(j); adj[j].pb(i);
            }
        }
        
    }
    int res;
    for (int i = 0; i < q; i++)
    {
        res = bfs(queries[i].first,queries[i].second);
        if(res==-1) cout<<"impossible\n";
        else cout<<res<<"\n";  
    }
    


    


    
}

signed main() {
    solve();
}

Compilation message (stderr)

events.cpp: In function 'long long int bfs(long long int, long long int)':
events.cpp:40:27: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   40 |         for (int i = 0; i < adj[cur].size(); i++)
      |                         ~~^~~~~~~~~~~~~~~~~

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