Submission #560669

#	Time	Username	Problem	Language	Result	Execution time	Memory
560669		colossal_pepe	Bitaro’s Party (JOI18_bitaro)	C++17	100 / 100	1625 ms	411420 KiB

bitaro

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
 
const int INF = 1e9;
const int BLOCK_SZ = 450;
 
int n, m, q;
vector<vector<int>> g;
vector<vector<pair<int, int>>> d;
 
void precomp() {
    int dist_from[n] = {0};
    for (int u = 0; u < n; u++) {
        vector<int> s;
        dist_from[u] = 0;
        s.push_back(u);
        for (int v : g[u]) {
            for (auto [x, y] : d[v]) {
                if (dist_from[y] >= x + 1) continue;
                if (dist_from[y] == 0) s.push_back(y);
                dist_from[y] = x + 1;
            }
        }
        sort(s.begin(), s.end(), [&dist_from](int i, int j) {
            return dist_from[i] < dist_from[j];
        });
        while (not s.empty()) {
            if (d[u].size() < BLOCK_SZ) d[u].push_back({dist_from[s.back()], s.back()});
            dist_from[s.back()] = 0;
            s.pop_back();
        }
    }
}
 
int getAns(int t, bool is_busy[]) {
    int i = 0;
    while (i < d[t].size() and is_busy[d[t][i].second]) i++;
    return (i < d[t].size() ? d[t][i].first : -1);
}
 
int comptueAns(int t, bool is_busy[]) {
    int dp[t + 1];
    for (int u = 0; u <= t; u++) {
        dp[u] = -INF;
        for (int v : g[u]) {
            dp[u] = max(dp[u], dp[v] + 1);
        }
        if (not is_busy[u]) dp[u] = max(dp[u], 0);
    }
    return max(dp[t], -1);
}
 
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cin >> n >> m >> q;
    g.resize(n), d.resize(n);
    while (m--) {
        int u, v;
        cin >> u >> v;
        u--, v--;
        g[v].push_back(u);
    }
    precomp();
    // for (int i = 0; i < n; i++) {
    //     for (auto [x, y] : d[i]) {
    //         cout << x << ' ' << y << " | ";
    //     }
    //     cout << '\n';
    // }
    vector<int> busy_ppl;
    bool is_busy[n] = {0};
    while (q--) {
        int t, y;
        cin >> t >> y;
        t--;
        busy_ppl.resize(y);
        for (int &c : busy_ppl) {
            cin >> c;
            c--;
            is_busy[c] = 1;
        }
        cout << (y < BLOCK_SZ ? getAns(t, is_busy) : comptueAns(t, is_busy)) << '\n';
        for (int &c : busy_ppl) {
            is_busy[c] = 0;
        }
        busy_ppl.clear();
    }
    return 0;
}

Compilation message (stderr)

bitaro.cpp: In function 'int getAns(int, bool*)':
bitaro.cpp:39:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   39 |     while (i < d[t].size() and is_busy[d[t][i].second]) i++;
      |            ~~^~~~~~~~~~~~~
bitaro.cpp:40:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   40 |     return (i < d[t].size() ? d[t][i].first : -1);
      |             ~~^~~~~~~~~~~~~

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