oj.uz

답안 #1085040

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
1085040 2024-09-07T11:39:41 Z djs100201 Event Hopping (BOI22_events) C++17
20 / 100
 205 ms 32152 KB 
#include <bits/stdc++.h>
#define all(v) v.begin(), v.end()
using namespace std;
using ll = long long;
using P = pair<ll, ll>;
using PP = pair<ll, P>;
const ll n_ = 1e5 + 10, inf = (ll)2e9 * (ll)1e9 + 7, mod = 998244353;
ll n, m, tc = 1, a, b, c, d, sum, x, y, z, base, ans, k;
ll S[n_], E[n_], par[n_][20], rev[n_];
bool cmp(ll x, ll y) { return E[x] < E[y]; }
class seg {
   public:
    vector<ll> tree;
    ll base;
    seg(int n) {
        for (base = 1; base <= n; base *= 2);
        // 0~n쓰겠다
        tree.resize(n * 4 + 4);
        for (int i = 0; i < tree.size(); i++) tree[i] = -inf;
    }
    ll f(ll l, ll r) {
        l += base, r += base;
        ll ret = -inf;
        while (l <= r) {
            if (l % 2) ret = max(ret, tree[l++]);
            if (!(r % 2)) ret = max(ret, tree[r--]);
            l /= 2, r /= 2;
        }
        return ret;
    }
    void update(ll i, ll v) {
        i += base;
        tree[i] = max(tree[i], v);
        i /= 2;
        while (i) {
            tree[i] = max(tree[i * 2], tree[i * 2 + 1]);
            i /= 2;
        }
    }
};
void solve() {
    ll Q;
    cin >> n >> Q;
    vector<ll> T, idx;
    for (int i = 1; i <= n; i++) {
        cin >> S[i] >> E[i];
        T.push_back(S[i]), T.push_back(E[i]);
        idx.push_back(i);
    }
    sort(all(idx), cmp), sort(all(T)), T.erase(unique(all(T)), T.end());
    seg ST(2 * n + 1);
    for (int i = 0; i < n; i++) {
        rev[idx[i]] = i;
        // cout<<idx[i]<<' '<<i<<endl;
        ll a = lower_bound(all(T), S[idx[i]]) - T.begin();
        ST.update(a, i);
    }
    for (int i = 0; i < n; i++) {
        ll l = lower_bound(all(T), S[idx[i]]) - T.begin(), r = lower_bound(all(T), E[idx[i]]) - T.begin();
        par[i][0] = ST.f(l, r);
    }
    for (int j = 1; j < 20; j++) {
        for (int i = 0; i < n; i++) {
            par[i][j] = par[par[i][j - 1]][j - 1];
        }
    }
    while (Q--) {
        cin >> x >> y;
        if (x == y) {
            cout << "0" << '\n';
            continue;
        }
        x = rev[x], y = rev[y];
        // if (E[idx[x]] > E[idx[y]]) swap(x, y);
        ll l = 0, r = n;
        ans = inf;
        while (l <= r) {
            ll mid = (l + r) / 2, now = x, cost = mid;
            for (int i = 19; i >= 0; i--) {
                if (cost >= (1ll << i)) {
                    cost -= (1ll << i);
                    now = par[now][i];
                }
            }
            if (E[idx[now]] >= S[idx[y]]) {
                ans = min(ans, mid);
                r = mid - 1;
            } else
                l = mid + 1;
        }
        ll now = x, cost = ans;
        for (int i = 19; i >= 0; i--) {
            if (cost >= (1ll << i)) {
                cost -= (1ll << i);
                now = par[now][i];
            }
        }
        if (E[idx[now]] < S[idx[y]] || E[idx[now]] > E[idx[y]])
            cout << "impossible" << '\n';
        else
            cout << ans + 1 << '\n';
    }
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    // cin >> tc;
    while (tc--) solve();
};

Compilation message

events.cpp: In constructor 'seg::seg(int)':
events.cpp:19:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   19 |         for (int i = 0; i < tree.size(); i++) tree[i] = -inf;
      |                         ~~^~~~~~~~~~~~~

Subtask #1
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 122 ms 31768 KB Output is correct
3 Correct 159 ms 31648 KB Output is correct
4 Correct 163 ms 31556 KB Output is correct
5 Incorrect 147 ms 31888 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #2
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 1 ms 604 KB Output is correct
4 Correct 1 ms 604 KB Output is correct
5 Incorrect 1 ms 604 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 1 ms 604 KB Output is correct
4 Correct 1 ms 604 KB Output is correct
5 Incorrect 1 ms 604 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 1 ms 604 KB Output is correct
4 Correct 1 ms 604 KB Output is correct
5 Incorrect 1 ms 604 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #5
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 123 ms 31640 KB Output is correct
2 Correct 162 ms 31724 KB Output is correct
3 Correct 171 ms 31556 KB Output is correct
4 Correct 119 ms 32068 KB Output is correct
5 Correct 205 ms 32152 KB Output is correct
6 Correct 184 ms 31816 KB Output is correct
7 Correct 170 ms 31808 KB Output is correct
8 Correct 162 ms 32068 KB Output is correct
9 Correct 78 ms 30020 KB Output is correct
10 Correct 128 ms 31552 KB Output is correct
11 Correct 117 ms 31380 KB Output is correct
12 Correct 131 ms 31492 KB Output is correct

Subtask #6
0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 122 ms 31768 KB Output is correct
3 Correct 159 ms 31648 KB Output is correct
4 Correct 163 ms 31556 KB Output is correct
5 Incorrect 147 ms 31888 KB Output isn't correct
6 Halted 0 ms 0 KB -