Submission #212889

#	Time	Username	Problem	Language	Result	Execution time	Memory
212889		dolphingarlic	Bitaro’s Party (JOI18_bitaro)	C++14	14 / 100	2103 ms	413048 KiB

bitaro

#include <bits/stdc++.h>
#define FOR(i, x, y) for (int i = x; i < y; i++)
using namespace std;

const int L = 350;

vector<int> graph[100001];
vector<pair<int, int>> sqrt_farthest[100001];
int a[100001], dp[100001], deg[100001], deg_cp[100001];
bool bad[100001], in_ret[100001];

vector<pair<int, int>> merge(vector<pair<int, int>> X, vector<pair<int, int>> Y) {
    vector<pair<int, int>> ret;
    int xptr = 0;
    for (int yptr = 0; ret.size() <= L && yptr < Y.size() && xptr < X.size(); yptr++) {
        while (xptr < X.size() && X[xptr].second >= Y[yptr].second) {
            if (!in_ret[X[xptr].first]) ret.push_back({X[xptr].first, X[xptr].second + 1});
            in_ret[X[xptr].first] = true;
            xptr++;
        }
        if (!in_ret[Y[yptr].first]) ret.push_back(Y[yptr]);
        in_ret[Y[yptr].first] = true;
    }
    while (xptr < X.size() && ret.size() <= L) {
        if (!in_ret[X[xptr].first]) ret.push_back({X[xptr].first, X[xptr].second + 1});
        in_ret[X[xptr].first] = true;
        xptr++;
    }
    for (pair<int, int> i : ret) in_ret[i.first] = false;
    return ret;
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n, m, k;
    cin >> n >> m >> k;
    FOR(i, 0, m) {
        int u, v;
        cin >> u >> v;
        graph[u].push_back(v);
        deg[v]++; deg_cp[v]++;
    }

    queue<int> q;
    FOR(i, 1, n + 1) {
        sqrt_farthest[i] = {{i, 0}};
        if (!deg_cp[i]) q.push(i);
    }
    while (q.size()) {
        int curr = q.front();
        q.pop();
        for (int i : graph[curr]) {
            sqrt_farthest[i] = merge(sqrt_farthest[curr], sqrt_farthest[i]);
            deg_cp[i]--;
            if (!deg_cp[i]) q.push(i);
        }
    }

    while (k--) {
        int t, y;
        cin >> t >> y;
        FOR(i, 0, y) {
            cin >> a[i];
            bad[a[i]] = true;
        }

        if (y >= L) {
            queue<int> q;
            FOR(i, 1, n + 1) {
                if (bad[i]) dp[i] = INT_MIN;
                else dp[i] = 0;
                deg_cp[i] = deg[i];
                if (!deg_cp[i]) q.push(i);
            }
            while (q.size()) {
                int curr = q.front();
                q.pop();
                for (int i : graph[curr]) {
                    dp[i] = max(dp[i], dp[curr] + 1);
                    deg_cp[i]--;
                    if (!deg_cp[i]) q.push(i);
                }
            }
            cout << max(-1, dp[t]) << '\n';
        } else {
            bool can = false;
            for (pair<int, int> i : sqrt_farthest[t]) if (!bad[i.first]) {
                can = true;
                cout << i.second << '\n';
                break;
            }
            if (!can) cout << "-1\n";
        }

        FOR(i, 0, y) bad[a[i]] = false;
    }
    return 0;
}

Compilation message (stderr)

bitaro.cpp: In function 'std::vector<std::pair<int, int> > merge(std::vector<std::pair<int, int> >, std::vector<std::pair<int, int> >)':
bitaro.cpp:15:48: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int yptr = 0; ret.size() <= L && yptr < Y.size() && xptr < X.size(); yptr++) {
                                           ~~~~~^~~~~~~~~~
bitaro.cpp:15:67: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int yptr = 0; ret.size() <= L && yptr < Y.size() && xptr < X.size(); yptr++) {
                                                              ~~~~~^~~~~~~~~~
bitaro.cpp:16:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         while (xptr < X.size() && X[xptr].second >= Y[yptr].second) {
                ~~~~~^~~~~~~~~~
bitaro.cpp:24:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while (xptr < X.size() && ret.size() <= L) {
            ~~~~~^~~~~~~~~~

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