Submission #1096225

#	Time	Username	Problem	Language	Result	Execution time	Memory
1096225		Zero_OP	Bitaro’s Party (JOI18_bitaro)	C++14	100 / 100	1088 ms	414804 KiB

bitaro

#include "bits/stdc++.h"

using namespace std;

#define sz(v) (int)v.size()
#define all(v) begin(v), end(v)
#define compact(v) v.erase(unique(all(v)), end(v))
#define rall(v) rbegin(v), rend(v)

const int MAX = 1e5 + 5;
int SQRT = 350;

int n, m, q, f[MAX];
vector<int> rev[MAX];
vector<pair<int, int>> dp[MAX]; //[dist, u]
bool bad[MAX];
bool vis[MAX];
int ptr[MAX];

void process(int u){
    vector<int> processed_vertices;
    for(int t = 0; t < SQRT + 2; ++t){
        pair<int, int> dist = {-1, -1};
        int num = 0;
        for(int v : rev[u]){
            while(ptr[v] < sz(dp[v])){
                if(vis[dp[v][ptr[v]].second]){
                    ++ptr[v];
                    continue;
                } else if(dp[v][ptr[v]].first + 1 > dist.first){
                    dist.first = dp[v][ptr[v]].first + 1;
                    dist.second = dp[v][ptr[v]].second;
                    num = v;
                }

                break;
            }
        }

        if(dist.first == -1) break;
        vis[dist.second] = true;
        processed_vertices.push_back(dist.second);
        dp[u].push_back(dist);
        ++ptr[num];
    }

    for(int v : rev[u]) ptr[v] = 0;
    for(int u : processed_vertices) vis[u] = false;
    dp[u].push_back({0, u});
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    if(fopen("task.inp", "r")){
        freopen("task.inp", "r", stdin);
        freopen("task.out", "w", stdout);
    }

    cin >> n >> m >> q;
    for(int i = 0; i < m; ++i){
        int u, v;
        cin >> u >> v;
        rev[v].push_back(u);
    }

    for(int i = 1; i <= n; ++i){
        sort(all(rev[i]));
        compact(rev[i]);
    }

    SQRT = sqrt(n);
    for(int i = 1; i <= n; ++i){
        process(i);
    }

//    return 0;

//    for(int i = 1; i <= n; ++i){
//        cout << i << " :\n";
//        for(auto j : best[i]) cout << j.first << ' ' << j.second << '\n'; cout << '\n';
//    }

    while(q--){
        int t, y;
        cin >> t >> y;

        vector<int> nodes(y);
        for(int i = 0; i < y; ++i) cin >> nodes[i];

        for(int u : nodes) bad[u] = true;

        if(y > SQRT){
//            cout << "heavy\n";
            fill(f + 1, f + 1 + n, -1e9);
            f[t] = 0;

            for(int i = t; i > 0; --i){
                for(int j : rev[i]){
                    f[j] = max(f[j], f[i] + 1);
                }
            }

            int ans = -1;
            for(int i = t; i > 0; --i){
                if(!bad[i]) ans = max(ans, f[i]);
            }

            cout << ans << '\n';
        } else{
//            cout << "light\n";
            int ans = -1;
            for(auto u : dp[t]){
                if(!bad[u.second]){
                    ans = u.first;
                    break;
                }
            }

            if(ans == -1){
                cout << ans << '\n';
            } else{
                cout << ans << '\n';
            }
        }

        for(int u : nodes) bad[u] = false;
    }

    return 0;
}

Compilation message (stderr)

bitaro.cpp: In function 'int main()':
bitaro.cpp:57:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   57 |         freopen("task.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
bitaro.cpp:58:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   58 |         freopen("task.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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