Submission #1191316

#	Time	Username	Problem	Language	Result	Execution time	Memory
1191316		MatteoArcari	Highway Tolls (IOI18_highway)	C++20	12 / 100	43 ms	8084 KiB

highway

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

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

void find_pair(int n, vector<int> u, vector<int> v, int a, int b) {
    int m = u.size();

    vector<int> w(m, 0);
    ll dst = ask(w) / a;

    vector<vector<int>> adj(n);

    for (int i = 0; i < m; i++) {
        adj[u[i]].push_back(i);
        adj[v[i]].push_back(i);
    }

    vector<int> d(n, -1), check, p(n);
    d[0] = 0;
    queue<int> q; q.push(0);
    while (!q.empty()) {
        int i = q.front();
        q.pop();
        if (d[i] == dst) {
            check.push_back(i);
            continue;
        }
        for (int _j: adj[i]) {
            int j = u[_j] ^ v[_j] ^ i;
            if (d[j] == -1) {
                p[j] = _j;
                d[j] = d[i] + 1;
                q.push(j);
            }
        }
    }

    while (check.size() > 1) {
        for (auto &x: w) x = 0;
        for (int i = 0; i < check.size(); i++) {
            if (i & 1) {
                w[p[check[i]]] = 1;
            }
        }
        vector<int> cc;
        int flag = ask(w) > a * dst;
        for (auto i: check) {
            if (w[p[i]] == flag) {
                cc.push_back(i);
            }
        }
        check = cc;
    }

    answer(0, check[0]);

}

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