Submission #561806

#	Time	Username	Problem	Language	Result	Execution time	Memory
561806		Cyanmond	Toll (APIO13_toll)	C++17	0 / 100	1 ms	212 KiB

toll

#include <bits/stdc++.h>

using namespace std;
using i64 = int64_t;

#define REP(i, n) for (int i = 0; i < (n); ++i)

template <typename T> void chmax(T &a, const T b) {
    if (a < b) a = b;
}

struct UnionFind {
    int n;
    vector<int> data;
    UnionFind(const int n_) : n(n_), data(n, -1) {}
    int find(int v) {
        if (data[v] < 0)
            return v;
        else
            return data[v] = find(data[v]);
    }
    int is_same(int a, int b) { return find(a) == find(b); }
    int size(int v) { return -data[find(v)]; }
    void unite(int a, int b) {
        a = find(a);
        b = find(b);
        if (a == b) return;
        if (size(a) < size(b)) swap(a, b);
        data[a] += data[b];
        data[b] = a;
    }
};

struct Merger {
    int n;
    vector<int> roots;
    vector<vector<int>> vals;
    Merger(const int n_) {
        n = n_;
        roots.assign(n, -1);
        REP(i, n) vals.push_back({i});
    }
    int find(int a) {
        if (roots[a] < 0)
            return a;
        else
            return roots[a] = find(roots[a]);
    }
    int size(int v) { return -roots[find(v)]; }
    void merge(int a, int b) {
        a = find(a);
        b = find(b);
        if (a == b) return;
        if (size(a) < size(b)) swap(a, b);
        for (const int e : vals[b]) vals[a].push_back(e);
        roots[a] += roots[b];
        roots[b] = a;
    }
};

struct Edge {
    int cost;
    int a;
    int b;
};

int main() {
    // ios::sync_with_stdio(false);
    // cin.tie(nullptr);

    int N, M, K;
    cin >> N >> M >> K;
    vector<Edge> E(M);
    REP(i, M) {
        cin >> E[i].a >> E[i].b >> E[i].cost;
        --E[i].a, --E[i].b;
    }
    vector<pair<int, int>> A(K);
    for (auto &[x, y] : A) {
        cin >> x >> y;
        --x, --y;
    }
    vector<i64> P(N);
    for (auto &e : P) cin >> e;

    {
        sort(E.begin(), E.end(), [](Edge a, Edge b) { return a.cost < b.cost; });
        UnionFind uft(N);
        REP(i, K) uft.unite(A[i].first, A[i].second);
        Merger mt(N);
        for (const auto &[cost, a, b] : E) {
            if (uft.is_same(a, b)) continue;
            uft.unite(a, b);
            mt.merge(a, b);
        }

        vector<bool> used(N);
        vector<vector<int>> groups;
        REP(i, N) {
            if (used[mt.find(i)]) continue;
            used[mt.find(i)] = true;
            groups.push_back(mt.vals[mt.find(i)]);
        }
        const int L = (int)size(groups);

        for (auto &g : groups) sort(g.begin(), g.end());
        sort(groups.begin(), groups.end(), [](auto &a, auto &b) { return a[0] < b[0]; });
        vector<int> att(N);
        REP(i, L) {
            const auto &g = groups[i];
            for (const int e : g) att[e] = i;
        }
        vector<i64> NP(L);
        REP(i, N) NP[att[i]] += P[i];
        P = move(NP);
        for (auto &[x, y] : A) {
            x = att[x];
            y = att[y];
        }
        REP(i, M) {
            E[i].a = att[E[i].a];
            E[i].b = att[E[i].b];
        }
        vector<Edge> E2;
        for (const auto &[cost, a, b] : E)
            if (a != b) E2.push_back({cost, a, b});
        E = E2;
        E2.clear();

        uft = UnionFind(L);
        for (const auto &[cost, a, b] : E) {
            if (uft.is_same(a, b)) continue;
            uft.unite(a, b);
            E2.push_back({cost, a, b});
        }
        E = move(E2);
        N = L;
        M = (int)size(E);
    }

    i64 ans = 0;
    REP(bit, 1 << K) {
        vector<vector<pair<int, int>>> tree(N);
        UnionFind uft(N);
        bool possible = true;
        REP(i, K) {
            if (bit & (1 << i)) {
                if (uft.is_same(A[i].first, A[i].second)) {
                    possible = false;
                    break;
                }
                uft.unite(A[i].first, A[i].second);
                tree[A[i].first].push_back({A[i].second, 1});
                tree[A[i].second].push_back({A[i].first, 1});
            }
        }
        if (not possible) continue;
        REP(i, M) {
            if (uft.is_same(E[i].a, E[i].b)) {
                auto dfs = [&](auto &&self, const int v, const int p) -> bool {
                    for (auto &[t, c] : tree[v]) {
                        if (t == p) continue;
                        if (t == E[i].b) {
                            if (c != 0) chmax(c, E[i].cost);
                            return true;
                        }
                        if (self(self, t, v)) {
                            chmax(c, E[i].cost);
                            return true;
                        }
                    }
                    return false;
                };
                assert(dfs(dfs, E[i].a, -1));
            } else {
                uft.unite(E[i].a, E[i].b);
                tree[E[i].a].push_back({E[i].b, 0});
                tree[E[i].b].push_back({E[i].a, 0});
            }
        }

        i64 res = 0;
        auto dfs = [&](auto &&self, const int v, const int p) -> i64 {
            i64 sum = 0;
            for (const auto &[t, c] : tree[v]) {
                if (t == p) continue;
                const i64 e = self(self, t, v);
                if (c != 0) res += c * e;
                sum += e;
            }
            return sum + P[v];
        };
        dfs(dfs, 0, -1);
        chmax(ans, res);
    }

    cout << ans << endl;
}

• Subtask 1: 0 / 16
• Subtask 2: 0 / 18
• Subtask 3: 0 / 22
• Subtask 4: 0 / 22
• Subtask 5: 0 / 22