Submission #764048

#	Time	Username	Problem	Language	Result	Execution time	Memory
764048		t6twotwo	통행료 (IOI18_highway)	C++17	18 / 100	210 ms	262144 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;
        }
    }
    ll s = ask(vector<int>(M));
    if (subtask3) {
        int lo = 0, hi = N - 1;
        while (lo < hi) {
            int mi = (lo + hi + 1) / 2;
            vector<int> w(M);
            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++) {
        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(M);
    //     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];
    // dfs(dfs, S, -1);
    vector<int> q;
    for (int i = 0; i < N; i++) {
        if (dep[i] == s / A) {
            q.push_back(i);
        }
    }
    int lo = 0, hi = q.size() - 1;
    while (lo < hi) {
        int mi = (lo + hi) / 2;
        vector<int> w(M);
        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]);
    answer(0, q[lo]);
}

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