Submission #806514

#	Time	Username	Problem	Language	Result	Execution time	Memory
806514		vjudge1	Event Hopping 2 (JOI21_event2)	C++17	7 / 100	222 ms	130304 KiB

event2

#ifdef Home
#define _GLIBCXX_DEBUG
#endif // Home

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;

struct node {
    int l, r, mx = 0;
    node *left = NULL, *right = NULL;

    node(int l, int r):l(l), r(r) {}
};

void check(node *x) {
    if(x->left == NULL) {
        x->left = new node(x->l, (x->l + x->r) / 2);
    }
    if(x->right == NULL) {
        x->right = new node((x->l + x->r) / 2, x->r);
    }
}

void update(int pos, int val, node *x) {
    if(x->l + 1 == x->r) {
        x->mx = val;
        return;
    }
    check(x);
    pos < x->left->r ?
    update(pos, val, x->left)  : 
    update(pos, val, x->right) ;
    x->mx = max(x->left->mx, x->right->mx);
}

int find(int r, node *x) {
    if(r <= x->l) {
        return x->mx;
    }
    check(x);
    int res = 0;
    if(x->left->r > r && x->left->mx) {
        res = find(r, x->left);
    }
    if(x->right->mx) {
        res = max(res, find(r, x->right));
    }
    return res;
}

main() {
#ifdef Home
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif // Home
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    
    bool tsk = true;
    int n, k, mxr = -1;
    cin >> n >> k;
    vector < pair < int, int > > V(n);
    for(int i = 0; i < n; ++ i) {
        cin >> V[i].first >> V[i].second;
        tsk &= (!i || V[i - 1].first <= V[i].first);
        mxr = max(mxr, V[i].second);
    }

    if(tsk) {
        int t = 1;
        for(; t <= mxr; t <<= 1);
        node *root = new node(0, t);
        int dp[n + 10];
        for(int i = n; i --> 0;) {
            dp[i] = 1 + find(V[i].second, root); 
            update(V[i].first, dp[i], root);
        }
        if(root->mx < k) {
            cout << -1;
            return 0;
        }
        for(int i = 0, j = 0; i < n && k; ++ i) {
            if(j <= V[i].first && k <= dp[i]) {
                cout << i + 1 << '\n';
                -- k;
                j = V[i].second;
            }
        }
        return 0;
    }
   
    int t = 1;
    for(; t <= mxr; t <<= 1);
    node *root = new node(0, t);
    vector < int > pos(n);
    iota(pos.begin(), pos.end(), 0);
    sort(pos.rbegin(), pos.rend(), [&](int i, int j) {
                return V[i] < V[j];
            });
    
    int dp[n + 10];
    for(auto &i : pos) {
        dp[i] = 1 + find(V[i].second, root); 
        update(V[i].first, dp[i], root);
    }
    if(root->mx < k) {
        cout << -1 << '\n';
        return 0;
    }
    bool use[n + 10] = {};
    for(int j = 0; k --> 0;) {
        for(int i = 0; i < n; ++ i) {
            if(!use[i] && j <= V[i].first && k < dp[i]) {
                use[i] = true;
                j = V[i].second;
                break;
            }
        }
    }
    for(int i = 0; i < n; ++ i) {
        if(use[i]) {
            cout << i + 1 << '\n';
        }
    }
} 

Compilation message (stderr)

event2.cpp:55:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   55 | main() {
      | ^~~~

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