Submission #338802

#	Time	Username	Problem	Language	Result	Execution time	Memory
338802		KoD	Cats or Dogs (JOI18_catdog)	C++17	38 / 100	33 ms	3436 KiB

catdog

#include <bits/stdc++.h>

template <class T>
using Vec = std::vector<T>;

constexpr int INF = 1000000000;

int N;
Vec<Vec<int>> graph;
Vec<int> state;
Vec<std::array<int, 2>> dp;

void initialize(int N_, Vec<int> A, Vec<int> B) {
    N = N_;
    assert(N <= 1000);
    graph.resize(N);
    state.resize(N, -1);
    dp.resize(N);
    for (int i = 0; i < N - 1; ++i) {
        graph[A[i] - 1].push_back(B[i] - 1);
        graph[B[i] - 1].push_back(A[i] - 1);
    }
}

void dfs(int u, int p) {
    dp[u][0] = 0;
    dp[u][1] = 0;
    for (auto v: graph[u]) {
        if (v != p) {
            dfs(v, u);
            dp[u][0] += std::min(dp[v][0], dp[v][1] + 1);
            dp[u][1] += std::min(dp[v][0] + 1, dp[v][1]);
        }
    }
    if (state[u] != -1) {
        dp[u][state[u] ^ 1] = INF;
    }
}

int solve() {
    for (int i = 0; i < N; ++i) {
        dp[i].fill(INF);
    }
    dfs(0, -1);
    return std::min(dp[0][0], dp[0][1]);
}

int cat(int u) {
    state[u - 1] = 0;
    return solve();
}

int dog(int u) {
    state[u - 1] = 1;
    return solve();
}

int neighbor(int u) {
    state[u - 1] = -1;
    return solve();
}

#ifdef __APPLE__
int main() {
    int N;
    std::cin >> N;
    Vec<int> A(N - 1), B(N - 1);
    for (int i = 0; i < N - 1; ++i) {
        std::cin >> A[i] >> B[i];
    }
    initialize(N, A, B);
    int Q;
    std::cin >> Q;
    for (int i = 0; i < N; ++i) {
        int T, v;
        std::cin >> T >> v;
        if (T == 1) {
            std::cout << cat(v) << '\n';
        }
        if (T == 2) {
            std::cout << dog(v) << '\n';
        }
        if (T == 3) {
            std::cout << neighbor(v) << '\n';
        }
    }
    return 0;
}
#endif

• Subtask 1: 8 / 8
• Subtask 2: 30 / 30
• Subtask 3: 0 / 62