oj.uz

Submission #253083

# Submission time Handle Problem Language Result Execution time Memory
253083 2020-07-26T21:22:03 Z Kubin Tropical Garden (IOI11_garden) C++17
100 / 100
 259 ms 39136 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);
    vector<size_t> st, src(2*n, nil); 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)
        {
            src[u] = s;
            st.push_back(u);

            if(src[F[u]] == s)
            {
                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(src[F[u]] != nil)
                break;
            u = F[u];
        }
        st.clear();
    }


    // 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 640 KB Output is correct
4 Correct 0 ms 384 KB Output is correct
5 Correct 1 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 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 1 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 640 KB Output is correct
10 Correct 0 ms 384 KB Output is correct
11 Correct 12 ms 5376 KB Output is correct
12 Correct 27 ms 8576 KB Output is correct
13 Correct 46 ms 24384 KB Output is correct
14 Correct 99 ms 28932 KB Output is correct
15 Correct 151 ms 29304 KB Output is correct
16 Correct 94 ms 20800 KB Output is correct
17 Correct 87 ms 17400 KB Output is correct
18 Correct 28 ms 8440 KB Output is correct
19 Correct 97 ms 28920 KB Output is correct
20 Correct 126 ms 29432 KB Output is correct
21 Correct 100 ms 20472 KB Output is correct
22 Correct 79 ms 17272 KB Output is correct
23 Correct 109 ms 32120 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 640 KB Output is correct
4 Correct 0 ms 384 KB Output is correct
5 Correct 1 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 640 KB Output is correct
10 Correct 0 ms 384 KB Output is correct
11 Correct 12 ms 5376 KB Output is correct
12 Correct 27 ms 8576 KB Output is correct
13 Correct 46 ms 24384 KB Output is correct
14 Correct 99 ms 28932 KB Output is correct
15 Correct 151 ms 29304 KB Output is correct
16 Correct 94 ms 20800 KB Output is correct
17 Correct 87 ms 17400 KB Output is correct
18 Correct 28 ms 8440 KB Output is correct
19 Correct 97 ms 28920 KB Output is correct
20 Correct 126 ms 29432 KB Output is correct
21 Correct 100 ms 20472 KB Output is correct
22 Correct 79 ms 17272 KB Output is correct
23 Correct 109 ms 32120 KB Output is correct
24 Correct 1 ms 384 KB Output is correct
25 Correct 14 ms 5376 KB Output is correct
26 Correct 27 ms 8576 KB Output is correct
27 Correct 240 ms 24384 KB Output is correct
28 Correct 103 ms 28920 KB Output is correct
29 Correct 170 ms 29560 KB Output is correct
30 Correct 135 ms 20728 KB Output is correct
31 Correct 95 ms 17272 KB Output is correct
32 Correct 28 ms 8440 KB Output is correct
33 Correct 126 ms 28920 KB Output is correct
34 Correct 153 ms 29304 KB Output is correct
35 Correct 108 ms 20344 KB Output is correct
36 Correct 99 ms 17272 KB Output is correct
37 Correct 109 ms 32108 KB Output is correct
38 Correct 259 ms 39136 KB Output is correct