oj.uz

Submission #253080

# Submission time Handle Problem Language Result Execution time Memory
253080 2020-07-26T21:14:45 Z Kubin Tropical Garden (IOI11_garden) C++17
69 / 100
 5000 ms 33392 KB 
// this is O(n+m+q) instead of O(m+nq) like the model solution
// why?

#include <functional>
#include <cstdint>
#include <cassert>
#include <climits>
#include <vector>
#include <array>

using namespace std;

const size_t nil = SIZE_MAX;

void answer(int);


void count_routes(int _n, int _m, int _t, int E[][2], int _q, int K[])
{
    const size_t n = _n, m = _m, target = _t, q = _q;

    // get edges
    vector<array<size_t, 2>> to(n, {nil, nil});
    for(size_t i = 0; i < m; i++)
    {
        size_t u = E[i][0], v = E[i][1];
        if(to[u][0] == nil)
            to[u][0] = v;
        else if(to[u][1] == nil)
            to[u][1] = v;
        if(to[v][0] == nil)
            to[v][0] = u;
        else if(to[v][1] == nil)
            to[v][1] = u;
    }

    vector<size_t> F(2*n, nil);
    // vertex i+n is vertex after coming through best edge of vertex i
    auto nfix = [&](size_t v, size_t u) {
        return v + (to[v][0] == u ? n : 0);
    };
    for(size_t u = 0; u < n; u++)
    {
        F[u] = nfix(to[u][0], u);
        F[u+n] = nfix(to[u][1] == nil ? to[u][0] : to[u][1], u);
    }

    // rho computation
    vector<bool> vis(2*n), on(2*n);
    vector<size_t> st; st.reserve(2*n);

    vector<size_t> top(2*n, nil);
    vector<int> lambda(2*n), omega(2*n);

    vector<vector<size_t>> G(2*n);

    for(size_t s = 0; s < 2*n; s++)
    {
        G[F[s]].push_back(s);
        // cout << s << " " << F[s] << endl;
        if(vis[s])
            continue;

        assert(st.empty());
        size_t u = s;
        while(true)
        {
            vis[u] = on[u] = true;
            st.push_back(u);

            if(on[F[u]])
            {
                vector<size_t> cycle;
                while(true)
                {
                    auto v = st.back(); st.pop_back();
                    on[v] = false;
                    cycle.push_back(v);
                    if(v == F[u])
                        break;
                }
                for(auto v : cycle)
                    omega[v] = cycle.size(), top[v] = v;
            }
            else if(vis[F[u]])
            {
                lambda[u] = lambda[F[u]] + 1;
                top[u] = top[F[u]];
            }
            else
                { u = F[u]; continue; }
            break;
        }
        while(not st.empty())
        {
            auto v = st.back(); st.pop_back();
            lambda[v] = lambda[F[v]] + 1;
            top[v] = top[F[v]];
            on[v] = false;
        }
    }


    // queries

    vector<pair<vector<int>, int>> tabs(2*n);
    function<pair<vector<int>, int>(size_t)> get_tab = [&](size_t t) -> pair<vector<int>, int> {
        if(not tabs[t].first.empty())
            return tabs[t];
        else if(lambda[t])
        {
            vector<int> cnt;
            function<void(size_t, size_t)> dfs = [&](size_t u, size_t d) {
                while(cnt.size() <= d) cnt.push_back(0);
                cnt[d] += (u < n);
                for(auto v : G[u])
                    dfs(v, d + 1);
            };
            dfs(t, 0);
            return tabs[t] = {cnt, 0};
        }
        else
        {
            size_t u = t;
            vector<int> cnt(omega[t]);
            for(int i = 0; i < omega[t]; i++, u = F[u])
            {
                int sh = (i ? omega[t] - i : 0);
                cnt[sh] += (u < n);
                sh++;
                for(auto v : G[u])
                  if(lambda[v])
                {
                    auto [sub, _] = get_tab(v);
                    (void)_;
                    while(cnt.size() < sh + sub.size()) cnt.push_back(0);
                    for(size_t d = 0; d < sub.size(); d++)
                        cnt[sh + d] += sub[d];
                }
            }
            for(size_t i = omega[t]; i < cnt.size(); i++)
                cnt[i] += cnt[i - omega[t]];
            return tabs[t] = {cnt, omega[t]};
        }
    };

    auto count = [&](int k, size_t t) {
        auto [T, mod] = get_tab(t);
        if(mod)
        {
            while((size_t)k >= T.size())
                k -= mod;
            return T[k];
        }
        else
            return (size_t)k < T.size() ? T[k] : 0;
    };

    for(size_t que = 0; que < q; que++)
    {
        int k = K[que];
        answer(count(k, target) + count(k, target + n));
    }
}

Subtask #1
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 640 KB Output is correct
2 Correct 1 ms 512 KB Output is correct
3 Correct 1 ms 640 KB Output is correct
4 Correct 0 ms 384 KB Output is correct
5 Correct 0 ms 256 KB Output is correct
6 Correct 1 ms 768 KB Output is correct
7 Correct 1 ms 384 KB Output is correct
8 Correct 1 ms 512 KB Output is correct
9 Correct 3 ms 640 KB Output is correct

Subtask #2
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 640 KB Output is correct
2 Correct 1 ms 512 KB Output is correct
3 Correct 1 ms 640 KB Output is correct
4 Correct 0 ms 384 KB Output is correct
5 Correct 0 ms 256 KB Output is correct
6 Correct 1 ms 768 KB Output is correct
7 Correct 1 ms 384 KB Output is correct
8 Correct 1 ms 512 KB Output is correct
9 Correct 3 ms 640 KB Output is correct
10 Correct 0 ms 384 KB Output is correct
11 Correct 12 ms 5504 KB Output is correct
12 Correct 26 ms 8824 KB Output is correct
13 Correct 47 ms 25016 KB Output is correct
14 Correct 147 ms 30080 KB Output is correct
15 Correct 153 ms 30456 KB Output is correct
16 Correct 96 ms 21496 KB Output is correct
17 Correct 104 ms 17784 KB Output is correct
18 Correct 26 ms 8832 KB Output is correct
19 Correct 144 ms 30072 KB Output is correct
20 Correct 183 ms 30456 KB Output is correct
21 Correct 107 ms 21368 KB Output is correct
22 Correct 115 ms 17788 KB Output is correct
23 Correct 127 ms 33392 KB Output is correct

Subtask #3
0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 640 KB Output is correct
2 Correct 1 ms 512 KB Output is correct
3 Correct 1 ms 640 KB Output is correct
4 Correct 0 ms 384 KB Output is correct
5 Correct 0 ms 256 KB Output is correct
6 Correct 1 ms 768 KB Output is correct
7 Correct 1 ms 384 KB Output is correct
8 Correct 1 ms 512 KB Output is correct
9 Correct 3 ms 640 KB Output is correct
10 Correct 0 ms 384 KB Output is correct
11 Correct 12 ms 5504 KB Output is correct
12 Correct 26 ms 8824 KB Output is correct
13 Correct 47 ms 25016 KB Output is correct
14 Correct 147 ms 30080 KB Output is correct
15 Correct 153 ms 30456 KB Output is correct
16 Correct 96 ms 21496 KB Output is correct
17 Correct 104 ms 17784 KB Output is correct
18 Correct 26 ms 8832 KB Output is correct
19 Correct 144 ms 30072 KB Output is correct
20 Correct 183 ms 30456 KB Output is correct
21 Correct 107 ms 21368 KB Output is correct
22 Correct 115 ms 17788 KB Output is correct
23 Correct 127 ms 33392 KB Output is correct
24 Correct 2 ms 384 KB Output is correct
25 Correct 14 ms 5540 KB Output is correct
26 Correct 41 ms 8832 KB Output is correct
27 Correct 243 ms 25144 KB Output is correct
28 Execution timed out 5069 ms 30072 KB Time limit exceeded
29 Halted 0 ms 0 KB -