Submission #417328

#	Time	Username	Problem	Language	Result	Execution time	Memory
417328		lyc	Event Hopping 2 (JOI21_event2)	C++14	7 / 100	40 ms	3384 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;
ii events[mxN];
int dp[mxN], mx[mxN];

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

    cin >> N >> K;
    FOR(i,1,N){
        int L, R; cin >> L >> R;
        events[i] = ii(L,R);
    }

    dp[N+1] = mx[N+1] = 0;
    dp[N] = mx[N] = 1;
    RFOR(i,N-1,1){
        auto it = lower_bound(events+1,events+1+N,ii(events[i].second,0))-events;
        dp[i] = mx[it]+1;
        mx[i] = max(mx[i+1], dp[i]);
    }

    vector<int> ans;
    FOR(i,1,N){
        if (ans.empty() || events[ans.back()].second <= events[i].first) {
            if (SZ(ans) + dp[i] >= K) {
                ans.push_back(i);
            }
        }

        if (SZ(ans) == K) break;
    }

    if (SZ(ans) < K) {
        cout << -1 << '\n';
    } else {
        for (int& x : ans) {
            cout << x << '\n';
        }
    }
}

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