Submission #853920

#	Time	Username	Problem	Language	Result	Execution time	Memory
853920		overwatch9	Bitaro’s Party (JOI18_bitaro)	C++17	0 / 100	1 ms	5464 KiB

bitaro

#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
using namespace std;
const int maxn = 1e5 + 1;
const int sqn = 320;
vector <int> adj[maxn], adjr[maxn];
bool blocked[maxn], visited[maxn], processed[maxn];
vector <int> topo;
int id[maxn];
void dfs(int s) {
    if (visited[s])
        return;
    visited[s] = true;
    for (auto i : adj[s])
        dfs(i);
    topo.push_back(s);
}
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n, m, q;
    cin >> n >> m >> q;
    for (int i = 0; i < m; i++) {
        int a, b;
        cin >> a >> b;
        adj[a].push_back(b);
        adjr[b].push_back(a);
    }
    vector <vector <pair <int, int>>> longest_paths(n+1);
    for (int i = 1; i <= n; i++) {
        longest_paths[i].push_back({0, i});
        for (auto j : adjr[i]) {
            for (auto x : longest_paths[j])
                longest_paths[i].push_back({x.first + 1, x.second});
        }
        sort(longest_paths[i].begin(), longest_paths[i].end());
        longest_paths[i].erase(unique(longest_paths[i].begin(), longest_paths[i].end()), longest_paths[i].end());
        sort(longest_paths[i].begin(), longest_paths[i].end(), greater <pair <int, int>> ());
        while (longest_paths[i].size() > sqn)
            longest_paths[i].pop_back();
    }
    while (q--) {
        int t, y;
        cin >> t >> y;
        fill(blocked, blocked + n + 1, false);
        for (int i = 0; i < y; i++) {
            int x;
            cin >> x;
            blocked[x] = true;
        }
        if (y < sqn) {
            int ans = -1;
            for (auto i : longest_paths[t]) {
                if (!blocked[i.second] && i.first > 0)
                    ans = max(ans, i.first);
            }
            cout << ans << '\n';
        } else {
            vector <int> dp(n+1, -1);
            for (int i = 1; i <= n; i++) {
                if (!blocked[i])
                    dp[i] = 0;
                for (auto j : adjr[i]) {
                    if (dp[j] != -1)
                        dp[i] = max(dp[i], dp[j] + 1);
                }
            }
            cout << dp[t] << '\n';
        }
    }
    
}

• Subtask 1: 0 / 7
• Subtask 2: 0 / 7
• Subtask 3: 0 / 86