Submission #1215017

#	Time	Username	Problem	Language	Result	Execution time	Memory
1215017		vanea	Bitaro’s Party (JOI18_bitaro)	C++20	100 / 100	778 ms	143380 KiB

bitaro

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

const int SQ = 100;
const int mxN = 1e5+10;

vector<int> adj[mxN];

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n, m, q;
    cin >> n >> m >> q;
    for(int i = 0; i < m; i++) {
        int a, b;
        cin >> a >> b;
        adj[b].push_back(a);
    }
    vector<vector<array<int, 2>>> paths(n+1);
    vector<int> from(n+1, -1);
    for(int i = 1; i <= n; i++) {
        paths[i].push_back({0, i});
        vector<int> from_idx;
        for(auto it : adj[i]) {
            for(auto [dist, idx] : paths[it]) {
                if(from[idx] == -1) {
                    from_idx.push_back(idx);
                    from[idx] = dist+1;
                }
                else {
                    from[idx] = max(from[idx], dist+1);
                }
            }
        }
        for(int j : from_idx) paths[i].push_back({from[j], j});
        sort(paths[i].rbegin(), paths[i].rend());
        while(paths[i].size() > SQ) paths[i].pop_back();
        for(int j : from_idx) from[j] = -1;
    }
    vector<bool> blocked(n+1);
    while(q--) {
        int t, y;
        cin >> t >> y;
        vector<int> now(y);
        for(int i = 0; i < y; i++) {
            cin >> now[i];
            blocked[now[i]] = true;
        }
        int ans = -1;
        if(y >= SQ) {
            vector<int> dp(t+1, -1);
            dp[t] = 0;
            for(int i = t; i >= 0; i--) {
                if(dp[i] == -1) continue;
                if(!blocked[i]) ans = max(ans, dp[i]);
                for(auto it : adj[i]) {
                    dp[it] = max(dp[it], dp[i]+1);
                }
            }
        }
        else {
            for(auto [dist, idx] : paths[t]) {
                if(blocked[idx]) continue;
                ans = dist;
                break;
            }
        }
        cout << ans << '\n';
        for(auto it : now) blocked[it] = false;
    }
    return 0;
}

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