oj.uz

Submission #253082

# Submission time Handle Problem Language Result Execution time Memory
253082 2020-07-26T21:20:51 Z Kubin Tropical Garden (IOI11_garden) C++17
100 / 100
 378 ms 36832 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<int> 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]])
            {
                size_t idx = find(st.begin(), st.end(), F[u]) - st.begin();
                for(size_t i = idx; i < st.size(); i++)
                    omega[st[i]] = st.size() - idx;
                st.resize(idx);
            }
            if(vis[F[u]])
                break;
            u = F[u];
        }
        while(not st.empty())
        {
            auto v = st.back(); st.pop_back();
            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(not omega[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(not omega[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)
        {
            if((size_t)k >= T.size())
                k = (k - T.size()) % mod + T.size();
            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 512 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 0 ms 384 KB Output is correct
8 Correct 1 ms 512 KB Output is correct
9 Correct 2 ms 512 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 512 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 0 ms 384 KB Output is correct
8 Correct 1 ms 512 KB Output is correct
9 Correct 2 ms 512 KB Output is correct
10 Correct 1 ms 384 KB Output is correct
11 Correct 12 ms 4992 KB Output is correct
12 Correct 24 ms 7936 KB Output is correct
13 Correct 45 ms 23104 KB Output is correct
14 Correct 92 ms 26872 KB Output is correct
15 Correct 116 ms 27256 KB Output is correct
16 Correct 90 ms 19320 KB Output is correct
17 Correct 75 ms 15992 KB Output is correct
18 Correct 25 ms 7936 KB Output is correct
19 Correct 96 ms 26892 KB Output is correct
20 Correct 119 ms 27256 KB Output is correct
21 Correct 89 ms 19064 KB Output is correct
22 Correct 75 ms 16120 KB Output is correct
23 Correct 96 ms 29832 KB Output is correct

Subtask #3
31.0 / 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 512 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 0 ms 384 KB Output is correct
8 Correct 1 ms 512 KB Output is correct
9 Correct 2 ms 512 KB Output is correct
10 Correct 1 ms 384 KB Output is correct
11 Correct 12 ms 4992 KB Output is correct
12 Correct 24 ms 7936 KB Output is correct
13 Correct 45 ms 23104 KB Output is correct
14 Correct 92 ms 26872 KB Output is correct
15 Correct 116 ms 27256 KB Output is correct
16 Correct 90 ms 19320 KB Output is correct
17 Correct 75 ms 15992 KB Output is correct
18 Correct 25 ms 7936 KB Output is correct
19 Correct 96 ms 26892 KB Output is correct
20 Correct 119 ms 27256 KB Output is correct
21 Correct 89 ms 19064 KB Output is correct
22 Correct 75 ms 16120 KB Output is correct
23 Correct 96 ms 29832 KB Output is correct
24 Correct 1 ms 384 KB Output is correct
25 Correct 14 ms 4992 KB Output is correct
26 Correct 25 ms 7928 KB Output is correct
27 Correct 278 ms 23104 KB Output is correct
28 Correct 96 ms 26872 KB Output is correct
29 Correct 119 ms 27256 KB Output is correct
30 Correct 98 ms 19448 KB Output is correct
31 Correct 77 ms 15992 KB Output is correct
32 Correct 27 ms 7928 KB Output is correct
33 Correct 106 ms 26860 KB Output is correct
34 Correct 212 ms 27256 KB Output is correct
35 Correct 119 ms 18936 KB Output is correct
36 Correct 120 ms 16252 KB Output is correct
37 Correct 122 ms 29816 KB Output is correct
38 Correct 378 ms 36832 KB Output is correct