Submission #1040958

#	Time	Username	Problem	Language	Result	Execution time	Memory
1040958		GrindMachine	Event Hopping 2 (JOI21_event2)	C++17	100 / 100	217 ms	44744 KiB

event2

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x,y) ((x+y-1)/(y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a,b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a,b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif

/*

read the solution a long time ago, remember some key ideas from there

*/

const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;
const int LOG = 17;

template<typename T>
struct sparse_table {
    /*============================*/

    T merge(T a, T b) {
        return max(a,b);
    }

    /*============================*/

    vector<vector<T>> table;
    vector<int> bin_log;
    int LOG = 0;

    sparse_table() {

    }

    sparse_table(vector<T> &a, int n) {
        while ((1 << LOG) <= n) LOG++;

        table = vector<vector<T>>(n, vector<T>(LOG));
        bin_log = vector<int>(n + 1);

        rep(i, n) table[i][0] = a[i];

        rep1(j, LOG - 1) {
            rep(i, n) {
                int jump = 1 << (j - 1);
                if (i + jump >= n) {
                    break;
                }

                table[i][j] = merge(table[i][j - 1], table[i + jump][j - 1]);
            }
        }

        bin_log[1] = 0;
        for (int i = 2; i <= n; ++i) {
            bin_log[i] = bin_log[i / 2] + 1;
        }
    }

    T query(int l, int r) {
        int len = r - l + 1;
        int k = bin_log[len];

        T val1 = table[l][k];
        T val2 = table[r - (1 << k) + 1][k];

        return merge(val1, val2);
    }
};

ll up[N][LOG];

void solve(int test_case)
{
    ll n,k; cin >> n >> k;
    vector<pll> a(n+5);
    rep1(i,n) cin >> a[i].ff >> a[i].ss;
    rep1(i,n) a[i].ss--;

    auto sa = a;
    rep1(i,n) swap(sa[i].ff,sa[i].ss);
    sort(sa.begin()+1,sa.begin()+n+1);

    set<pll> st;
    st.insert({-inf1,-inf1});
    st.insert({inf1,inf1});

    auto ok = [&](ll l, ll r){
        auto it1 = st.lower_bound({l+1,-1});
        it1--;
        auto it2 = st.lower_bound({r+1,-1});
        it2--;
        if(it1 != it2) return false;
        auto [lx,rx] = *it1;
        if((lx <= l and l <= rx) or (lx <= r and r <= rx)) return false;
        return true;        
    };

    vector<ll> ls(n+5);
    rep1(i,n) ls[i] = sa[i].ss;
    sparse_table<ll> sparse(ls,n+1);

    auto f = [&](ll lx, ll rx){
        ll p = lower_bound(sa.begin()+1,sa.begin()+n+1,pll{lx,-1})-sa.begin();
        ll lo = p, hi = n;
        ll first = -1;

        while(lo <= hi){
            ll mid = (lo+hi) >> 1;
            if(sparse.query(p,mid) >= lx){
                first = mid;
                hi = mid-1;
            }
            else{
                lo = mid+1;
            }
        }

        if(first == -1) return 0ll;
        if(sa[first].ff > rx) return 0ll;

        ll i = first;
        ll cnt = 1;

        rev(j,LOG-1,0){
            auto [r2,l2] = sa[up[i][j]];
            if(r2 > rx) conts;
            cnt += 1<<j;
            i = up[i][j];
        }

        return cnt;
    };

    sa[n+1] = {inf1,inf1};
    vector<ll> nxt(n+5,n+1);
    rev(i,n,1){
        auto [r,l] = sa[i];
        ll lo = i+1, hi = n;
        while(lo <= hi){
            ll mid = (lo+hi) >> 1;
            if(sparse.query(i+1,mid) > r){
                nxt[i] = mid;
                hi = mid-1;
            }
            else{
                lo = mid+1;
            }
        }
    }

    rep1(i,n+1) up[i][0] = nxt[i];
    rep1(j,LOG-1){
        rep1(i,n+1){
            up[i][j] = up[up[i][j-1]][j-1];
        }
    }

    ll cnt = f(-inf1+1,inf1-1);
    if(cnt < k){
        cout << -1 << endl;
        return;
    }

    vector<ll> ans;

    rep1(i,n){
        if(sz(ans) == k) break;

        auto [l,r] = a[i];
        if(!ok(l,r)) conts;
        st.insert({l,r});
        auto it = st.find({l,r});

        auto [pl,pr] = *prev(it);
        auto [nl,nr] = *next(it);
        ll curr_cnt = cnt+1;
        curr_cnt -= f(pr+1,nl-1);
        curr_cnt += f(pr+1,l-1);
        curr_cnt += f(r+1,nl-1);

        if(curr_cnt >= k){
            ans.pb(i);
            cnt = curr_cnt;
        }
        else{
            st.erase(it);
        }
    }

    assert(sz(ans) == k);
    trav(x,ans) cout << x << endl;
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;

    rep1(i, t) {
        solve(i);
    }

    return 0;
}

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