oj.uz

Submission #779529

# Submission time Handle Problem Language Result Execution time Memory
779529 2023-07-11T13:52:32 Z CpDark Event Hopping (BOI22_events) C++14
0 / 100
 96 ms 17468 KB 
#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int, int> pii;
typedef vector<pii> vp;
typedef vector<vp> vvp;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<ll> vll;
typedef vector<vll> vvll;

const ll inf = 1e18 + 7;

vvp table;
vp events;
vector<pair<int, pii>> endTimes;
int mylog;

int jumpK(int end, int k) {
    for (int i = mylog;i >= 0;i--) {
        if ((k >> i) & 1) {
            end = table[i][end].first;
        }
    }
    return end;
}

bool check(int start, int end, int jumps) {
    int wall = events[start].second;
    int far = jumpK(end, jumps);
    if (events[far].second <= wall && events[start].first <= events[far].first)return true;
    return false;
}

int binSearch(int l, int r, int start, int end) {
    if (!check(start, end, r + 1)) return -1;
    
    while (l < r)
    {
        int m = l + (r - l) / 2;
        if (check(start, end, m)) {
            r = m;
        }
        else {
            l = m + 1;
        }
    }
    return l;
}

int query(int start, int end, int n) {
    if (events[start].second > events[end].second)return -1;
    int ans = binSearch(0, n, start, end);
    return ans;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    
    int n, q;
    cin >> n >> q;
    mylog = ceil(log2(n + 1));
    events.resize(n);
    endTimes.resize(n);
    table.resize(mylog + 1, vp(n));
    
    for (int i = 0;i < n;i++) {
        cin >> events[i].first >> events[i].second;
        endTimes[i] = { events[i].second, {events[i].first, i} };
    }

    sort(endTimes.begin(), endTimes.end());

    for (int i = 0;i < endTimes.size();i++) {
        int index = endTimes[i].second.second;
        int far = lower_bound(endTimes.begin(), endTimes.end(), (pair<int, pii>){ events[index].first, make_pair(-1,-1)}) - endTimes.begin();
        table[0][index] = { endTimes[far].second.second, endTimes[far].first};
    }

    for (int i = 1;i <= mylog;i++) {
        for (int v = 0;v < n;v++) {
            int p = table[i - 1][v].first;
            table[i][v] = table[i - 1][p];
        }
    }

    int s, e;
    for (int i = 0;i < q;i++) {
        cin >> s >> e;
        s--; e--;
        int ans = query(s, e, n);
        if (ans == -1) {
            cout << "impossible\n";
        }
        else {
            cout << ans << '\n';
        }
    }

    return 0;
}

Compilation message

events.cpp: In function 'int main()':
events.cpp:78:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, std::pair<int, int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   78 |     for (int i = 0;i < endTimes.size();i++) {
      |                    ~~^~~~~~~~~~~~~~~~~

Subtask #1
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 336 KB Output is correct
2 Correct 96 ms 17180 KB Output is correct
3 Incorrect 56 ms 17420 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Incorrect 1 ms 340 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Incorrect 1 ms 340 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Incorrect 1 ms 340 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #5
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 94 ms 17108 KB Output is correct
2 Incorrect 59 ms 17468 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 336 KB Output is correct
2 Correct 96 ms 17180 KB Output is correct
3 Incorrect 56 ms 17420 KB Output isn't correct
4 Halted 0 ms 0 KB -