Submission #417031

#	Time	Username	Problem	Language	Result	Execution time	Memory
417031		lyc	Event Hopping 2 (JOI21_event2)	C++14	32 / 100	3045 ms	5156 KiB

event2

#include <bits/stdc++.h>
using namespace std;

#define TRACE(x) cerr << #x << " :: " << x << endl
#define _ << " " <<
#define SZ(x) ((int)(x).size())
#define ALL(x) (x).begin(), (x).end()
#define FOR(i,a,b) for(int i=(a);i<=(b);++i)
#define RFOR(i,a,b) for(int i=(a);i>=(b);--i)
typedef long long ll;
typedef pair<int,int> ii;

const int mxN = 1e5+5;
const int mxK = 1e5+5;

int N, K;
struct Event { int L, R, I; };
vector<Event> events, byR;
int dp[mxN], used[mxN], ans[mxK];

int solve(int lb, int rb) {
    int ret = 0, ep = -1;
    for (auto& e : byR) if (lb <= e.L && e.R <= rb) {
        if (e.L >= ep) {
            ++ret;
            ep = e.R;
        }
    }

    return ret;
}

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

    cin >> N >> K;
    FOR(i,1,N){
        int L, R; cin >> L >> R;
        events.push_back({L,R,i});
        byR.push_back({L,R,i});
    }
    sort(ALL(byR), [&](Event a, Event b){ return a.R < b.R; });

    set<ii> cur;
    cur.insert(ii(-1,-1));
    cur.insert(ii(1e9+5,1e9+5));
    ll take = solve(-1,1e9+5);
    for (auto& e : events) {
        auto it = cur.lower_bound(ii(e.L, 0));
        if (e.R > it->first) continue;
        if (prev(it)->second > e.L) continue;

        ll take2 = take;
        take2 -= solve(prev(it)->second, it->first);
        take2 += solve(prev(it)->second, e.L);
        take2 += solve(e.R, it->first);
        take2 += 1;

        if (take2 >= K) {
            cur.insert(ii(e.L,e.R));
            take = take2;
            used[e.I] = 1;
        }

        if (SZ(cur)-2 >= K) break;
    }

    if (SZ(cur)-2 < K) {
        cout << -1 << '\n';
    }

    FOR(i,1,N) if (used[i] && K) {
        cout << i << '\n';
        --K;
    }
}

• Subtask 1: 0 / 7
• Subtask 2: 1 / 1
• Subtask 3: 31 / 31
• Subtask 4: 0 / 61