Submission #386292

#	Time	Username	Problem	Language	Result	Execution time	Memory
386292		model_code	Event Hopping 2 (JOI21_event2)	C++17	100 / 100	258 ms	28800 KiB

event2

#include <algorithm>
#include <iostream>
#include <set>
#include <vector>
using namespace std;

constexpr int MAX_N = 100'000;
constexpr int MAX_logN = 18;
constexpr int MAX_LR = 1'000'000'000;

int N, K;
int L[MAX_N], R[MAX_N];
vector<int> z;

vector<int> invL[MAX_N * 2 + 1];
int doubling[MAX_N * 2 + 1][MAX_logN];
int count(int l, int r) {
    int res = 0;
    for (int j = MAX_logN - 1; j >= 0; j--) {
        if (doubling[l][j] <= r) {
            l = doubling[l][j];
            res += 1 << j;
        }
    }
    return res;
}

int main() {
    scanf("%d%d", &N, &K);
    for (int i = 0; i < N; i++) {
        scanf("%d%d", L + i, R + i);
        z.push_back(L[i]);
        z.push_back(R[i]);
    }
    sort(z.begin(), z.end());
    z.erase(unique(z.begin(), z.end()), z.end());
    for (int i = 0; i < N; i++) {
        L[i] = lower_bound(z.begin(), z.end(), L[i]) - z.begin();
        R[i] = lower_bound(z.begin(), z.end(), R[i]) - z.begin();
    }

    for (int i = 0; i < N; i++) invL[L[i]].push_back(i);
    int r = z.size();
    for (int i = z.size(); i >= 0; i--) {
        for (int j = 0; j < invL[i].size(); j++) r = min(r, R[invL[i][j]]);
        doubling[i][0] = r;
    }
    for (int i = 1; i < MAX_logN; i++) {
        for (int j = 0; j <= z.size(); j++) {
            doubling[j][i] = doubling[doubling[j][i - 1]][i - 1];
        }
    }

    int now = count(0, z.size() - 1);
    if (now < K) {
        printf("-1\n");
        return 0;
    }
    set<pair<int, int>> used = {{0, 0}, {z.size() - 1, z.size() - 1}};
    for (int i = 0; used.size() - 2 < K; i++) {
        int l = prev(used.lower_bound({R[i], 0}))->second;
        int r = used.lower_bound({R[i], 0})->first;
        if (L[i] < l) continue;
        int tmp = now - count(l, r) + count(l, L[i]) + 1 + count(R[i], r);
        if (tmp >= K) {
            printf("%d\n", i + 1);
            now = tmp;
            used.insert({L[i], R[i]});
        }
    }
}

Compilation message (stderr)

event2.cpp: In function 'int main()':
event2.cpp:45:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   45 |         for (int j = 0; j < invL[i].size(); j++) r = min(r, R[invL[i][j]]);
      |                         ~~^~~~~~~~~~~~~~~~
event2.cpp:49:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   49 |         for (int j = 0; j <= z.size(); j++) {
      |                         ~~^~~~~~~~~~~
event2.cpp:60:37: warning: comparison of integer expressions of different signedness: 'std::set<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   60 |     for (int i = 0; used.size() - 2 < K; i++) {
      |                     ~~~~~~~~~~~~~~~~^~~
event2.cpp:29:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   29 |     scanf("%d%d", &N, &K);
      |     ~~~~~^~~~~~~~~~~~~~~~
event2.cpp:31:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   31 |         scanf("%d%d", L + i, R + i);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~

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