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답안 #253088

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
253088 2020-07-26T21:25:19 Z Kubin 열대 식물원 (Tropical Garden) (IOI11_garden) C++17
100 / 100
 270 ms 39208 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);
        if(vis[s])
            continue;

        assert(st.empty());
        size_t u = s;
        while(src[u] == nil)
        {
            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);
            }
            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();
            if((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

# 결과 실행 시간 메모리 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 384 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 3 ms 640 KB Output is correct

Subtask #2
20.0 / 20.0

# 결과 실행 시간 메모리 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 384 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 3 ms 640 KB Output is correct
10 Correct 0 ms 384 KB Output is correct
11 Correct 11 ms 5376 KB Output is correct
12 Correct 24 ms 8568 KB Output is correct
13 Correct 46 ms 24384 KB Output is correct
14 Correct 96 ms 28996 KB Output is correct
15 Correct 131 ms 29432 KB Output is correct
16 Correct 91 ms 20728 KB Output is correct
17 Correct 86 ms 17272 KB Output is correct
18 Correct 27 ms 8444 KB Output is correct
19 Correct 97 ms 28920 KB Output is correct
20 Correct 123 ms 29304 KB Output is correct
21 Correct 92 ms 20472 KB Output is correct
22 Correct 77 ms 17272 KB Output is correct
23 Correct 98 ms 32248 KB Output is correct

Subtask #3
31.0 / 31.0

# 결과 실행 시간 메모리 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 384 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 3 ms 640 KB Output is correct
10 Correct 0 ms 384 KB Output is correct
11 Correct 11 ms 5376 KB Output is correct
12 Correct 24 ms 8568 KB Output is correct
13 Correct 46 ms 24384 KB Output is correct
14 Correct 96 ms 28996 KB Output is correct
15 Correct 131 ms 29432 KB Output is correct
16 Correct 91 ms 20728 KB Output is correct
17 Correct 86 ms 17272 KB Output is correct
18 Correct 27 ms 8444 KB Output is correct
19 Correct 97 ms 28920 KB Output is correct
20 Correct 123 ms 29304 KB Output is correct
21 Correct 92 ms 20472 KB Output is correct
22 Correct 77 ms 17272 KB Output is correct
23 Correct 98 ms 32248 KB Output is correct
24 Correct 1 ms 384 KB Output is correct
25 Correct 13 ms 5376 KB Output is correct
26 Correct 26 ms 8568 KB Output is correct
27 Correct 270 ms 24384 KB Output is correct
28 Correct 97 ms 29048 KB Output is correct
29 Correct 139 ms 29436 KB Output is correct
30 Correct 97 ms 20876 KB Output is correct
31 Correct 76 ms 17272 KB Output is correct
32 Correct 39 ms 8440 KB Output is correct
33 Correct 131 ms 28992 KB Output is correct
34 Correct 139 ms 29432 KB Output is correct
35 Correct 103 ms 20344 KB Output is correct
36 Correct 97 ms 17272 KB Output is correct
37 Correct 117 ms 32140 KB Output is correct
38 Correct 261 ms 39208 KB Output is correct