Submission #853926

#	Time	Username	Problem	Language	Result	Execution time	Memory
853926		overwatch9	Bitaro’s Party (JOI18_bitaro)	C++17	7 / 100	1950 ms	524288 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];
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});
        vector <int> curr, dis(n+1);
        vector <bool> vis(n+1);
        for (auto j : adjr[i]) {
            for (auto x : longest_paths[j]) {
                if (vis[x.second] == i)
                    dis[x.second] = max(dis[x.second], x.first + 1);
                else {
                    dis[x.second] = x.first + 1;
                    curr.push_back(x.second);
                }
            }
        } 
        for (auto j : curr)
            longest_paths[i].push_back({dis[j], j});
        sort(longest_paths[i].begin(), longest_paths[i].end(), greater <pair <int, int>> ());
        if (longest_paths[i].size() > sqn)  
            longest_paths[i].erase(longest_paths[i].begin() + sqn + 1, longest_paths[i].end());
    }
    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])
                    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: 7 / 7
• Subtask 2: 0 / 7
• Subtask 3: 0 / 86