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Submission #1086473

# Submission time Handle Problem Language Result Execution time Memory
1086473 2024-09-10T17:51:01 Z vjudge1 Event Hopping (BOI22_events) C++17
30 / 100
 214 ms 16748 KB 
#include<bits/stdc++.h>
using namespace std;

int const N = 1e5+10;

struct interval {
    int s, e;
    interval() = default;
    interval(int a, int b) : s(a), e(b) {}
    bool operator< (const interval& o) const {
        if (s == o.s) return e > o.e;
        return s < o.s;
    }
} IT[N];

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
struct node {
    interval it; 
    int idx, meta, prior;
    node *l, *r;
    node() = default;
    node(int i) : it(IT[i]), idx(i), meta(i), prior(rng()), l(0), r(0) {}
};
using pnode = node*;

pnode rt = nullptr;
void update(pnode u) {
    if (!u) return;
    u->meta = u->idx;
    if (u->l && IT[u->l->meta].e > IT[u->meta].e) u->meta = u->l->meta;
    if (u->r && IT[u->r->meta].e > IT[u->meta].e) u->meta = u->r->meta;
}
void split(pnode rt, pnode& l, pnode& r, int v) {
    if (!rt) return (void)(l=r=nullptr);
    if (v < rt->it.s) split(rt->l, l, rt->l, v), r = rt;
    else split(rt->r, rt->r, r, v), l = rt;
    update(rt);
}
void split(pnode rt, pnode& l, pnode& r, interval it) {
    if (!rt) return (void)(l=r=nullptr);
    if (it < rt->it) split(rt->l, l, rt->l, it), r = rt;
    else split(rt->r, rt->r, r, it), l = rt;
    update(rt);
}
void join(pnode& rt, pnode l, pnode r) {
    if (!l || !r) rt = l?:r;
    else if (l->prior > r->prior) join(l->r, l->r, r), rt = l;
    else join(r->l, l, r->l), rt = r;
    update(rt);
}
void add(int idx) {
    if (rt == nullptr) rt = new node(idx);
    else {
        pnode nn = new node(idx);
        pnode lv, rv;
        split(rt, lv, rv, nn->it);
        join(rt, lv, nn); join(rt, rt, rv);
    }
}

int sparse[17][N];
void dfs(pnode r) {
    if (!r) return;
    dfs(r->l);
    cerr << "[" << r->it.s << ", " << r->it.e << "] ";
    dfs(r->r);
}


int main() {
    ios::sync_with_stdio(false); cin.tie(nullptr);
    int n, q; cin >> n >> q;
    for (int i = 1; i <= n; ++i) {
        cin >> IT[i].s >> IT[i].e;
        add(i);
    }
    //dfs(rt); cerr << '\n';
    for (int i = 1; i <= n; ++i) {
        pnode lv, rv; split(rt, lv, rv, IT[i].e);
        //dfs(lv);
        //cerr << lv->meta << ' ';
        sparse[0][i] = lv->meta;
        join(rt, lv, rv);
    }
    //cerr << '\n';
    for (int b = 1; b < 17; ++b) {
        for (int i = 1; i <= n; ++i) sparse[b][i] = sparse[b-1][sparse[b-1][i]];
    }
    for (int i = 0; i < q; ++i) {
        int a, b; cin >> a >> b;
        if (a == b) {
            cout << 0 << '\n';
            continue;
        }


        if (IT[a].e > IT[b].e) {
            cout << "impossible\n";
        }
        else {
            int st = 0;
            for (int bb = 16; ~bb; --bb) {
                int idx = sparse[bb][a];
                if (IT[idx].e < IT[b].e) {
                    st += 1<<bb;
                    a = idx;
                }
            }
            if (IT[a].e >= IT[b].s) {
                ++st;
                cout << st << '\n';
            }
            else {
                ++st; a = sparse[0][a];
                if (IT[a].e != IT[b].e) {
                    cout << "impossible\n";
                }
                else {
                    cout << (st+1) << '\n';
                }
            }
        }
    }

}

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 171 ms 16084 KB Output is correct
3 Correct 206 ms 16204 KB Output is correct
4 Correct 196 ms 16080 KB Output is correct
5 Correct 214 ms 16248 KB Output is correct
6 Correct 212 ms 16212 KB Output is correct
7 Correct 213 ms 16288 KB Output is correct
8 Correct 195 ms 16724 KB Output is correct
9 Correct 166 ms 16748 KB Output is correct
10 Correct 187 ms 16400 KB Output is correct
11 Correct 209 ms 16648 KB Output is correct
12 Correct 70 ms 15948 KB Output is correct

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 1 ms 548 KB Output is correct
4 Correct 1 ms 604 KB Output is correct
5 Incorrect 1 ms 600 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 1 ms 548 KB Output is correct
4 Correct 1 ms 604 KB Output is correct
5 Incorrect 1 ms 600 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 1 ms 548 KB Output is correct
4 Correct 1 ms 604 KB Output is correct
5 Incorrect 1 ms 600 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #5
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 166 ms 16092 KB Output is correct
2 Correct 177 ms 16212 KB Output is correct
3 Correct 183 ms 16184 KB Output is correct
4 Correct 170 ms 16720 KB Output is correct
5 Correct 184 ms 16468 KB Output is correct
6 Correct 189 ms 16212 KB Output is correct
7 Correct 185 ms 16208 KB Output is correct
8 Correct 176 ms 16464 KB Output is correct
9 Correct 90 ms 14420 KB Output is correct
10 Correct 177 ms 16000 KB Output is correct
11 Correct 153 ms 15820 KB Output is correct
12 Correct 194 ms 15820 KB Output is correct

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 348 KB Output is correct
2 Correct 171 ms 16084 KB Output is correct
3 Correct 206 ms 16204 KB Output is correct
4 Correct 196 ms 16080 KB Output is correct
5 Correct 214 ms 16248 KB Output is correct
6 Correct 212 ms 16212 KB Output is correct
7 Correct 213 ms 16288 KB Output is correct
8 Correct 195 ms 16724 KB Output is correct
9 Correct 166 ms 16748 KB Output is correct
10 Correct 187 ms 16400 KB Output is correct
11 Correct 209 ms 16648 KB Output is correct
12 Correct 70 ms 15948 KB Output is correct
13 Correct 0 ms 344 KB Output is correct
14 Correct 0 ms 348 KB Output is correct
15 Correct 1 ms 548 KB Output is correct
16 Correct 1 ms 604 KB Output is correct
17 Incorrect 1 ms 600 KB Output isn't correct
18 Halted 0 ms 0 KB -