Submission #893812

#	Time	Username	Problem	Language	Result	Execution time	Memory
893812		vjudge1	Event Hopping 2 (JOI21_event2)	C++17	100 / 100	188 ms	42412 KiB

event2

#include <bits/stdc++.h>

using namespace std;

#define all(x) x.begin(), x.end()
#define ar array
#define pb push_back
#define ln '\n'
#define int long long

using i64 = long long;

template <class F, class _S>
bool chmin(F &u, const _S &v){
    bool flag = false;
    if ( u > v ){
        u = v; flag |= true;
    }
    return flag;
}

template <class F, class _S>
bool chmax(F &u, const _S &v){
    bool flag = false;
    if ( u < v ){
        u = v; flag |= true;
    }
    return flag;
}

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, k; cin >> n >> k;
    vector <int> L(n), R(n);
    for ( int i = 0; i < n; i++ ){
        cin >> L[i] >> R[i];
    }
    { // compression
        vector <int> p_;
        for ( int i = 0; i < n; i++ ){
            p_.pb(L[i]);
            p_.pb(R[i]);
        }
        sort(all(p_));
        p_.resize(unique(all(p_)) - p_.begin());
        auto get = [&](int x){
            return lower_bound(all(p_), x) - p_.begin() + 1;
        };
        for ( int i = 0; i < n; i++ ){
            L[i] = get(L[i]);
            R[i] = get(R[i]);
        }
    }
    int m = n * 2;
    const int inf = m + 1;
    vector <int> qu(m + 1, inf);
    for ( int i = 0; i < n; i++ ){
        chmin(qu[L[i]], R[i]);
    }
    vector <vector<int>> up(20, vector <int> (m + 2, inf));
    for ( int i = m; i > 0; i-- ){
        up[0][i] = min(qu[i], up[0][i + 1]);
    }
    for ( int i = 1; i < 20; i++ ){
        for ( int j = 1; j <= m; j++ ){
            up[i][j] = up[i - 1][up[i - 1][j]];
        }
    }
    auto dp = [&](int l, int r){
        int cnt = 0;
        for ( int i = 19; i >= 0; i-- ){
            if ( up[i][l] <= r ){
                l = up[i][l];
                cnt |= 1 << i;
            }
        }
        return cnt;
    };
    int tot = dp(1, m);
    if ( tot < k ){
        return cout << "-1", 0;
    }
    set <pair<int,int>> st{{1, m}};
    vector <int> ans;
    for ( int i = 0; i < n; i++ ){
        auto it = prev(st.lower_bound({L[i] + 1, -1}));
        auto [l, r] = *it;
        if ( r >= R[i] ){
            int nxt = tot - dp(l, r) + dp(l, L[i]) + dp(R[i], r) + 1;
            if ( nxt >= k ){
                swap(nxt, tot);
                ans.pb(i);
                st.erase(it);
                st.insert({l, L[i]});
                st.insert({R[i], r});
            }
        }
    }
    for ( int i = 0; i < k; i++ ){
        cout << ans[i] + 1 << ln;
    }

    cout << '\n';
}

• Subtask 1: 7 / 7
• Subtask 2: 1 / 1
• Subtask 3: 31 / 31
• Subtask 4: 61 / 61