Submission #656515

#	Time	Username	Problem	Language	Result	Execution time	Memory
656515		Lobo	Event Hopping (BOI22_events)	C++17	0 / 100	1572 ms	13768 KiB

events

#include<bits/stdc++.h>
using namespace std;
const long long inf = (long long) 1e18 + 10;
const int inf1 = (int) 1e9 + 10;
#define int long long
#define dbl long double
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()

const int maxn = 1e5+10;

int n, q, lf[maxn], rg[maxn], sq[maxn], eq[maxn], ansq[maxn], nx[maxn];
vector<int> qrys[maxn];
void solve() {
    cin >> n >> q;
    vector<pair<pair<int,int>,int>> ord; // first smaller rg and smaller lf
    for(int i = 1; i <= n; i++) {
        cin >> lf[i] >> rg[i];
        ord.pb(mp(mp(rg[i],lf[i]),i));
    }
    sort(all(ord));

    for(int i = 1; i <= q; i++) {
        cin >> sq[i] >> eq[i];
        qrys[eq[i]].pb(i);
    }

    for(int i = 1; i <= n; i++) {
        nx[i] = -1;
    }


    for(auto X : ord) {
        int i = X.sc;
        for(int j = 1; j <= n; j++) {
            //from j to i
            if(lf[i] <= rg[j] && rg[j] < rg[i] && j != i) {
                nx[j] = i;
            }
            if(rg[i] == rg[j] && lf[j] < lf[i]) {
                nx[j] = i;
            }
        }
        // cout << i << endl;

        for(auto id : qrys[i]) {
            // cout << " " << id << endl;
            int j = sq[id];
            if(i == j) {
                ansq[id] = 0;
                break;
            }
            if(rg[j] == rg[i]) {
                ansq[id] = 1;
                break;
            }
            int cnt = 0;
            while(j != -1) {
                j = nx[j];
                cnt++;
                if(j == i) break;
            }
            if(j == -1) {
                ansq[id] = -1;
            }
            else {
                ansq[id] = cnt;
            }
        }
    }

    for(int i = 1; i <= q; i++) {
        if(ansq[i] == -1) cout << "impossible" << endl;
        else cout << ansq[i] << endl;
    }
}

int32_t main() {
    ios::sync_with_stdio(false); cin.tie(0);

    // freopen("in.in", "r", stdin);
    // freopen("out.out", "w", stdout);
    int tt = 1;
    // cin >> tt;
    while(tt--) {
        solve();
    }

}

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