Submission #1079659

#	Time	Username	Problem	Language	Result	Execution time	Memory
1079659		skittles1412	Highway Tolls (IOI18_highway)	C++17	90 / 100	202 ms	17104 KiB

highway

#include "bits/extc++.h"

using namespace std;

template <typename T, typename... U>
void dbgh(const T& t, const U&... u) {
    cerr << t;
    ((cerr << " | " << u), ...);
    cerr << endl;
}

#ifdef DEBUG
#define dbg(...)                                              \
    cerr << "L" << __LINE__ << " [" << #__VA_ARGS__ << "]: "; \
    dbgh(__VA_ARGS__)
#else
#define dbg(...)
#define cerr   \
    if (false) \
    cerr
#endif

using ll = long long;

#define endl "\n"
#define long int64_t
#define sz(x) int(std::size(x))

inline void init_io() {
    cin.tie(nullptr);
    cin.exceptions(ios::failbit);
    ios_base::sync_with_stdio(false);
}

template <typename T>
vector<T> iota(int n, T x) {
    vector<T> ans(n);
    iota(begin(ans), end(ans), x);
    return ans;
}

template <typename T>
vector<T>& operator+=(vector<T>& a, const vector<T>& b) {
    a.insert(end(a), begin(b), end(b));
    return a;
}

template <typename T>
vector<T> operator+(vector<T> a, const vector<T>& b) {
    return a += b;
}

template <typename Cb>
struct CmpByKey {
    Cb cb;

    CmpByKey(Cb cb) : cb(cb) {}

    template <typename T>
    bool operator()(const T& a, const T& b) const {
        return cb(a) < cb(b);
    }
};

template <typename T, typename Cb>
T first_true(T l, T r, const Cb& cb) {
    while (l < r) {
        T mid = (l + r) / 2;

        if (cb(mid)) {
            r = mid;
        } else {
            l = mid + 1;
        }
    }

    return l;
}

template <typename T, typename Cb>
T last_true(T l, T r, const Cb& cb) {
    while (l < r) {
        T mid = (l + r + 1) / 2;

        if (cb(mid)) {
            l = mid;
        } else {
            r = mid - 1;
        }
    }

    return l;
}

template <typename T>
ostream& operator<<(ostream& out, const vector<T>& arr) {
    out << "[";
    for (int i = 0; i < sz(arr); i++) {
        if (i) {
            out << ", ";
        }
        out << arr[i];
    }
    return out << "]";
}

template <typename T>
T negated(T arr) {
    for (auto& a : arr) {
        a = -a;
    }
    return arr;
}

template <typename A, typename B>
ostream& operator<<(ostream& out, const pair<A, B>& p) {
    return out << "(" << p.first << ", " << p.second << ")";
}

ll ask(const std::vector<int>& w);
void answer(int s, int t);

pair<vector<int>, vector<pair<int, int>>> bfs(const vector<vector<int>>& graph,
                                              int src) {
    int n = sz(graph);

    vector dist(n, -1);
    queue<int> q;
    vector<pair<int, int>> tedges;

    auto push = [&](int u, int src, int d) -> void {
        if (dist[u] != -1) {
            return;
        }

        dist[u] = d;
        q.push(u);
        if (src != -1) {
            tedges.emplace_back(src, u);
        }
    };

    push(src, -1, 0);

    while (sz(q)) {
        int u = q.front();
        q.pop();

        for (auto& v : graph[u]) {
            push(v, u, dist[u] + 1);
        }
    }

    return {dist, tedges};
}

void solve(int n, const vector<pair<int, int>>& edges, int wa, int) {
    int m = sz(edges);
    dbg(m);

    vector<vector<pair<int, int>>> graph(n);

    for (int i = 0; i < m; i++) {
        auto& [u, v] = edges[i];
        graph[u].emplace_back(v, i);
        graph[v].emplace_back(u, i);
    }

    long base = ask(vector<int>(m, 0));

    auto nodes_blocked = [&](const vector<int>& nodes) -> vector<int> {
        vector<int> cv(m);

        for (auto& u : nodes) {
            for (auto& [_v, ei] : graph[u]) {
                cv[ei] = true;
            }
        }

        return cv;
    };
    auto ask_nodes = [&](const vector<int>& nodes) -> bool {
        return ask(nodes_blocked(nodes)) > base;
    };

    int root = first_true(0, n, [&](int x) -> bool {
        return ask_nodes(iota(x + 1, 0));
    });
    dbg(root);

    auto base_block = iota(root, 0);
    dbg(base_block);

    auto [dist, tedges] = bfs([&]() {
        vector<vector<int>> graph(n);

        for (auto& [u, v] : edges) {
            if (u >= root && v >= root) {
                graph[u].push_back(v);
                graph[v].push_back(u);
            }
        }

        return graph;
    }(), root);
    dbg(tedges);
    auto ord = iota(n, 0);
    sort(begin(ord), end(ord), CmpByKey([&](int u) -> int {
        return dist[u];
    }));

    int u1_ind = last_true(0, n,
                           [&](int x) -> bool {
        return ask_nodes(base_block + vector(begin(ord) + x, end(ord)));
    }),
        u1 = ord[u1_ind];

    if (dist[u1] == base / wa) {
        answer(u1, root);
        return;
    }

    dbg(u1);
    vector<int> rem_nodes;
    {
        vector<vector<int>> graph(n);
        for (auto& [u, v] : tedges) {
            graph[u].push_back(v);
            graph[v].push_back(u);
        }

        vector<bool> vis(n);
        vector<int> q;

        for (int i = 0; i <= root; i++) {
            vis[i] = true;
        }

        auto push = [&](int u) -> void {
            if (vis[u]) {
                return;
            }
            vis[u] = true;
            q.push_back(u);
        };

        push(u1);
        while (sz(q)) {
            int u = q.back();
            q.pop_back();

            for (auto& v : graph[u]) {
                push(v);
            }
        }

        for (auto& a : ord) {
            if (!vis[a]) {
                rem_nodes.push_back(a);
            }
        }
    }

    int u2_ind = last_true(0, sz(rem_nodes),
                           [&](int x) -> bool {
        return ask_nodes(base_block +
                         vector(begin(rem_nodes) + x, end(rem_nodes)));
    }),
        u2 = rem_nodes[u2_ind];

    dbg(u1, u2);
    dbg(ord, u1_ind, u2_ind);
    answer(u1, u2);
}

void find_pair(int n,
               vector<int> edges_u,
               vector<int> edges_v,
               int wa,
               int wb) {
    return solve(n, [&]() {
        vector<pair<int, int>> cv;

        for (int i = 0; i < sz(edges_u); i++) {
            cv.emplace_back(edges_u[i], edges_v[i]);
        }

        return cv;
    }(), wa, wb);
}

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 6 / 6
• Subtask 4: 33 / 33
• Subtask 5: 18 / 18
• Subtask 6: 21 / 31