oj.uz

Submission #615435

# Submission time Handle Problem Language Result Execution time Memory
615435 2022-07-31T09:10:45 Z KoD Mousetrap (CEOI17_mousetrap) C++17
100 / 100
 1046 ms 198736 KB 
#include <bits/stdc++.h>

using std::vector;

template <class F> struct fixed : private F {
    explicit fixed(F&& f) : F(std::forward<F>(f)) {}
    template <class... Args> decltype(auto) operator()(Args&&... args) const {
        return F::operator()(*this, std::forward<Args>(args)...);
    }
};

int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);
    int N, T, M;
    std::cin >> N >> T >> M;
    T -= 1, M -= 1;
    vector<vector<int>> graph(N);
    for (int e = 1; e < N; ++e) {
        int a, b;
        std::cin >> a >> b;
        a -= 1, b -= 1;
        graph[a].push_back(b);
        graph[b].push_back(a);
    }
    vector<int> parent(N);
    parent[T] = -1;
    fixed([&](auto&& dfs, const int u) -> void {
        for (const int v : graph[u]) {
            if (v != parent[u]) {
                parent[v] = u;
                dfs(v);
            }
        }
    })(T);
    vector<int> path;
    vector<char> on_path(N);
    for (int u = M; u != T; u = parent[u]) {
        path.push_back(u);
        on_path[u] = true;
    }
    on_path[T] = true;
    const int L = (int)path.size();
    vector<vector<int>> dp(L);
    for (int i = 0; i < L; ++i) {
        for (const int src : graph[path[i]]) {
            if (!on_path[src]) {
                dp[i].push_back(fixed([&](auto&& dfs, const int u) -> int {
                    vector<int> list;
                    for (const int v : graph[u]) {
                        if (v != parent[u]) {
                            list.push_back(dfs(v));
                        }
                    }
                    const int n = (int)list.size();
                    std::sort(list.rbegin(), list.rend());
                    return (n >= 2 ? list[1] : 0) + n;
                })(src));
            }
        }
    }
    vector<int> above(L);
    for (int i = L - 1; i > 0; --i) {
        above[i - 1] = above[i] + (int)graph[path[i]].size() - 2;
    }
    const auto check = [&](const int thres) {
        int cut = 0;
        for (int i = 0; i < L; ++i) {
            const int offset = cut + above[i] + (int)dp[i].size();
            for (const int x : dp[i]) {
                if (offset + x > thres) {
                    if (cut > i) {
                        return false;
                    }
                    cut += 1;
                }
            }
        }
        return cut <= thres;
    };
    int ok = N, ng = -1;
    while (ok - ng > 1) {
        const int md = (ok + ng) / 2;
        (check(md) ? ok : ng) = md;
    }
    std::cout << ok << '\n';
    return 0;
}

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 212 KB Output is correct
9 Correct 1 ms 212 KB Output is correct
10 Correct 1 ms 212 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 389 ms 63584 KB Output is correct
2 Correct 313 ms 66016 KB Output is correct
3 Correct 968 ms 74240 KB Output is correct
4 Correct 427 ms 37132 KB Output is correct
5 Correct 960 ms 74396 KB Output is correct
6 Correct 928 ms 74244 KB Output is correct

Subtask #3
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 212 KB Output is correct
9 Correct 1 ms 212 KB Output is correct
10 Correct 1 ms 212 KB Output is correct
11 Correct 0 ms 320 KB Output is correct
12 Correct 1 ms 340 KB Output is correct
13 Correct 1 ms 340 KB Output is correct
14 Correct 1 ms 340 KB Output is correct
15 Correct 1 ms 340 KB Output is correct
16 Correct 1 ms 328 KB Output is correct
17 Correct 1 ms 340 KB Output is correct
18 Correct 1 ms 340 KB Output is correct
19 Correct 1 ms 324 KB Output is correct
20 Correct 1 ms 324 KB Output is correct
21 Correct 1 ms 340 KB Output is correct
22 Correct 1 ms 340 KB Output is correct

Subtask #4
35.0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 212 KB Output is correct
9 Correct 1 ms 212 KB Output is correct
10 Correct 1 ms 212 KB Output is correct
11 Correct 389 ms 63584 KB Output is correct
12 Correct 313 ms 66016 KB Output is correct
13 Correct 968 ms 74240 KB Output is correct
14 Correct 427 ms 37132 KB Output is correct
15 Correct 960 ms 74396 KB Output is correct
16 Correct 928 ms 74244 KB Output is correct
17 Correct 0 ms 320 KB Output is correct
18 Correct 1 ms 340 KB Output is correct
19 Correct 1 ms 340 KB Output is correct
20 Correct 1 ms 340 KB Output is correct
21 Correct 1 ms 340 KB Output is correct
22 Correct 1 ms 328 KB Output is correct
23 Correct 1 ms 340 KB Output is correct
24 Correct 1 ms 340 KB Output is correct
25 Correct 1 ms 324 KB Output is correct
26 Correct 1 ms 324 KB Output is correct
27 Correct 1 ms 340 KB Output is correct
28 Correct 1 ms 340 KB Output is correct
29 Correct 0 ms 212 KB Output is correct
30 Correct 356 ms 73284 KB Output is correct
31 Correct 354 ms 73268 KB Output is correct
32 Correct 425 ms 139296 KB Output is correct
33 Correct 447 ms 198736 KB Output is correct
34 Correct 1034 ms 74436 KB Output is correct
35 Correct 1046 ms 74324 KB Output is correct
36 Correct 980 ms 83704 KB Output is correct
37 Correct 1000 ms 83744 KB Output is correct
38 Correct 799 ms 85608 KB Output is correct
39 Correct 864 ms 85544 KB Output is correct
40 Correct 783 ms 85608 KB Output is correct