제출 #764058

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
764058		t6twotwo	통행료 (IOI18_highway)	C++17	51 / 100	142 ms	16548 KiB

highway

#include "highway.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
void find_pair(int N, vector<int> U, vector<int> V, int A, int B) {
    int M = U.size();
    bool subtask3 = M == N - 1;
    for (int i = 0; i < M; i++) {
        if (U[i] != i && V[i] != i + 1) {
            subtask3 = 0;
        }
    }
    vector<int> p(N);
    iota(p.begin(), p.end(), 0);
    function<int(int)> find = [&](int x) {
        return x == p[x] ? x : p[x] = find(p[x]);
    };
    auto unite = [&](int x, int y) {
        p[find(x)] = find(y);
    };
    vector<int> W(M);
    for (int i = 0; i < M; i++) {
        if (find(U[i]) == find(V[i])) {
            W[i] = 1;
        } else {
            unite(U[i], V[i]);
        }
    }
    ll s = ask(W);
    if (subtask3) {
        int lo = 0, hi = N - 1;
        while (lo < hi) {
            int mi = (lo + hi + 1) / 2;
            vector<int> w(W);
            fill(w.begin(), w.begin() + mi, 1);
            if (ask(w) != s) {
                hi = mi - 1;
            } else {
                lo = mi;
            }
        }
        answer(lo, lo + s / A);
        return;
    }
    vector<vector<pair<int, int>>> adj(N);
    for (int i = 0; i < M; i++) {
        if (W[i]) {
            continue;
        }
        adj[U[i]].emplace_back(V[i], i);
        adj[V[i]].emplace_back(U[i], i);
    }
    vector<int> dep(N), t(N);
    auto dfs = [&](auto dfs, int x, int p) -> void {
        for (auto [y, z] : adj[x]) {
            if (y == p) {
                continue;
            }
            t[y] = z;
            dep[y] = dep[x] + 1;
            dfs(dfs, y, x);
        }
    };
    dfs(dfs, 0, -1);
    vector<vector<int>> v(N);
    for (int i = 0; i < N; i++) {
        v[dep[i]].push_back(i);
    }
    int lo = 1, hi = N - 1;
    while (lo < hi) {
        int mi = (lo + hi) / 2;
        vector<int> w(M, 1);
        for (int i = 1; i <= mi; i++) {
            for (int x : v[i]) {
                w[t[x]] = 0;
            }
        }
        if (ask(w) == s) {
            hi = mi;
        } else {
            lo = mi + 1;
        }
    }
    int d = lo; lo = 0, hi = v[d].size() - 1;
    while (lo < hi) {
        int mi = (lo + hi) / 2;
        vector<int> w(W);
        for (int i = 0; i <= mi; i++) {
            w[t[v[d][i]]] = 1;
        }
        if (ask(w) != s) {
            hi = mi;
        } else {
            lo = mi + 1;
        }
    }
    int S = v[d][lo];
    dep[S] = 0;
    dfs(dfs, S, -1);
    vector<int> q;
    for (int i = 0; i < N; i++) {
        if (dep[i] == s / A) {
            q.push_back(i);
        }
    }
    lo = 0, hi = q.size() - 1;
    while (lo < hi) {
        int mi = (lo + hi) / 2;
        vector<int> w(W);
        for (int i = 0; i <= mi; i++) {
            w[t[q[i]]] = 1;
        }
        if (ask(w) != s) {
            hi = mi;
        } else {
            lo = mi + 1;
        }
    }
    answer(S, q[lo]);
}

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 6 / 6
• Subtask 4: 33 / 33
• Subtask 5: 0 / 18
• Subtask 6: 0 / 31