Submission #576334

#	Time	Username	Problem	Language	Result	Execution time	Memory
576334		eecs	Through Another Maze Darkly (CCO21_day1problem3)	C++17	4 / 25	5437 ms	1048576 KiB

Main

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

typedef long long ll;
const int maxn = 800010;
int n, q, ptr[maxn], fa[maxn];
bool vis[maxn];
vector<int> G[maxn];

int main() {
    ios::sync_with_stdio(0), cin.tie(0);
    cin >> n >> q;
    for (int i = 1, k; i <= n; i++) {
        cin >> k;
        while (k--) {
            int c;
            cin >> c, G[i].push_back(c);
        }
    }
    auto dfs = [&](auto self, int u) -> void {
        for (int v : G[u]) if (v ^ fa[u]) {
            fa[v] = u, self(self, v);
        }
    };
    dfs(dfs, 1);
    vector<int> tmp;
    ll step = 0;
    for (int u = 1, cnt = 0; cnt < n || u > 1; step++) {
        if (!vis[u]) vis[u] = 1, cnt++;
        tmp.push_back(u = G[u][++ptr[u] %= G[u].size()]);
    }
    int u = 1;
    vector<int> res;
    for (int i = 0; i < 2 * n - 2; i++) {
        res.push_back(u), u = G[u][++ptr[u] %= G[u].size()];
    }
    while (q--) {
        ll k;
        cin >> k;
        if (k < step) cout << tmp[k - 1] << "\n";
        else cout << res[(k - step) % (2 * n - 2)] << "\n";
    }
    return 0;
}

• Subtask 1: 0 / 4
• Subtask 2: 4 / 4
• Subtask 3: 0 / 12
• Subtask 4: 0 / 5