oj.uz

Submission #679222

# Submission time Handle Problem Language Result Execution time Memory
679222 2023-01-07T18:58:27 Z bebra Boat (APIO16_boat) C++17
0 / 100
 2000 ms 50580 KB 
#include <bits/stdc++.h>
using namespace std;

#define dbg(x) cerr << #x << ": " << x << endl;


struct Seg {
    int l;
    int r;

    Seg(int _l = -1, int _r = -1) : l(_l), r(_r) {}


    bool empty() const {
        return r - l + 1 <= 0;
    }

    bool operator<(const Seg& other) const {
        return tie(l, r) < tie(other.l, other.r);
    }

    bool operator==(const Seg& other) const {
        return tie(l, r) == tie(other.l, other.r);
    }

    friend Seg intersect(const Seg& lhs, const Seg& rhs) {
        return {max(lhs.l, rhs.l), min(lhs.r, rhs.r)};
    }
};


const int MOD = 1e9 + 7;
const int INV2 = 500000004;

int add(int a, int b) {
    int res = a + b;
    if (res >= MOD) res -= MOD;
    return res;
}

int mul(long long a, int b) {
    return a * b % MOD;
}

const int MAX_N = 500 + 1;
Seg segs[MAX_N];
vector<Seg> states[MAX_N];
vector<int> dp[MAX_N];
int main_idx[MAX_N];


int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int n;
    cin >> n;
    for (int i = 1; i <= n; ++i) {
        cin >> segs[i].l >> segs[i].r;
        states[i].push_back(segs[i]);
    }
    segs[0] = {-1, -1};
    states[0].emplace_back(-1, -1);
    dp[0].assign(1, 1);
    int ans = 0;
    for (int i = 1; i <= n; ++i) {
        vector<int> ls;
        vector<int> rs;
        for (int j = 1; j <= n; ++j) {
            if (segs[j].l >= segs[i].l) {
                ls.push_back(segs[j].l);
            }
            if (segs[j].r <= segs[i].r) {
                rs.push_back(segs[j].r);
            }
        }
        sort(ls.begin(), ls.end());
        ls.resize(unique(ls.begin(), ls.end()) - ls.begin());
        sort(rs.begin(), rs.end());
        rs.resize(unique(rs.begin(), rs.end()) - rs.begin());
        for (auto l : ls) {
            for (auto r : rs) {
                if (l <= r) {
                    states[i].emplace_back(l, r);
                }
            }
        }
        for (auto l1 : ls) {
            for (auto l2 : ls) {
                if (l2 - 1 >= l1) {
                    states[i].emplace_back(l1, l2 - 1);
                }
            }
        }
        sort(states[i].begin(), states[i].end());
        states[i].resize(unique(states[i].begin(), states[i].end()) - states[i].begin());
        dp[i].resize(states[i].size());
        main_idx[i] = lower_bound(states[i].begin(), states[i].end(), segs[i]) - states[i].begin();

        int m = states[i].size();
        for (int j = 0; j < m; ++j) {
            auto [l1, r1] = states[i][j];
            for (int k = 0; k < i; ++k) {
                auto [l2, r2] = segs[k];
                if (r1 < l2) {
                    continue;
                }
                if (r2 < l1) {
                    dp[i][j] = add(dp[i][j], mul(dp[k][main_idx[k]], r1 - l1 + 1));
                    continue;
                }
                auto [l3, r3] = intersect(states[i][j], segs[k]);

                dp[i][j] = add(dp[i][j], mul(dp[k][main_idx[k]], r1 - r3));

                int idx1 = lower_bound(states[k].begin(), states[k].end(), Seg{l3, r3}) - states[k].begin();
                dp[i][j] = add(dp[i][j], mul(dp[k][idx1], mul(r3 - l3, INV2)));

                if (l3 - 1 >= l2) {
                    int idx2 = lower_bound(states[k].begin(), states[k].end(), Seg{l2, l3 - 1}) - states[k].begin();
                    dp[i][j] = add(dp[i][j], mul(r3 - l1 + 1, dp[k][idx2]));
                }
            }
        }
        ans = add(ans, dp[i][main_idx[i]]);
    }
    cout << ans << '\n';
    return 0;
}


/*
10
1 2
2 3
3 4
4 5
5 6
6 7
7 8
8 9
9 10
10 11
*/

Subtask #1
0 / 9.0

# Verdict Execution time Memory Grader output
1 Execution timed out 2083 ms 50580 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Execution timed out 2083 ms 50580 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #3
0 / 27.0

# Verdict Execution time Memory Grader output
1 Incorrect 755 ms 4036 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Execution timed out 2083 ms 50580 KB Time limit exceeded
2 Halted 0 ms 0 KB -