Submission #982763

#	Time	Username	Problem	Language	Result	Execution time	Memory
982763		kh0i	Bitaro’s Party (JOI18_bitaro)	C++17	100 / 100	1278 ms	267040 KiB

bitaro

#include "bits/stdc++.h"
using namespace std;

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...)
#endif

using ll = long long;
using pii = pair<int, int>;

#define F first
#define S second
#define sz(x) (int)((x).size())
#define all(x) (x).begin(), (x).end()

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll get_rand(ll l, ll r) {
    assert(l <= r);
    return uniform_int_distribution<ll> (l, r)(rng);
}

const int N = 1e5 + 3;
const int B = 320;

int n, m, q;
vector<int> g[N], rg[N];
vector<pii> best_paths[N];
bool vis[N];
int c[N];
bool busy[N];
int f[N];

void prep(){ // B largest paths to each node
    for(int i = 1; i <= n; ++i){
        best_paths[i].push_back({i, 0});
        for(int p : rg[i]){
            // avoid repeated sources
            // merge sort

            vector<pii> yoin;
            int x = 0, y = 0;

            while(x < sz(best_paths[p]) or y < sz(best_paths[i])){
                if(sz(yoin) == B)
                    break;

                while(x < sz(best_paths[p]) and vis[best_paths[p][x].F])
                    ++x;
                while(y < sz(best_paths[i]) and vis[best_paths[i][y].F])
                    ++y;

                pii u = (x < sz(best_paths[p]) ? best_paths[p][x] : make_pair(-1, -1));
                pii v = (y < sz(best_paths[i]) ? best_paths[i][y] : make_pair(-1, -1));

                if(u.F != -1 and u.S + 1 > v.S){
                    u.S += 1;
                    yoin.push_back(u);
                    vis[u.F] = 1;
                    ++x;
                }
                else if(v.F != -1){
                    yoin.push_back(v);
                    vis[v.F] = 1;
                    ++y;
                }
            }

            best_paths[i] = yoin;
            for(int j = 0; j < sz(yoin); ++j)
                vis[yoin[j].F] = 0;
        }
        debug(i, best_paths[i]);
    }
}

void solve(){
    cin >> n >> m >> q;
    for(int i = 1; i <= m; ++i){
        int u, v;
        cin >> u >> v;
        rg[v].push_back(u);
    }
    prep();
    while(q--){
        int t, y;
        cin >> t >> y;
        for(int i = 1; i <= y; ++i){
            cin >> c[i];
            busy[c[i]] = 1;
        }
        if(y < B){
            int res = -1;
            for(auto [v, x] : best_paths[t])
                if(!busy[v])
                    res = max(res, x);
            if(!busy[t])
                res = max(res, 0);
            cout << res << '\n';
        }

        else{
            memset(f, -1, sizeof(f));
            for(int i = 1; i <= t; ++i){
                if(!busy[i])
                    f[i] = 0;
                for(int v : rg[i])
                    if(f[v] != -1)
                        f[i] = max(f[i], f[v] + 1);
            }
            cout << f[t] << '\n';
        }

        for(int i = 1; i <= y; ++i)
            busy[c[i]] = 0;
    }
}

int32_t main() {
    cin.tie(nullptr)->sync_with_stdio(0);
    #define task "troll"
    if(fopen(task".inp", "r")){
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    int test = 1;
//    cin >> test;
    for(int i = 1; i <= test; ++i){
//        cout << "Case #" << i << ": ";
        solve();
    }
    #ifdef LOCAL
        cerr << "\n[Time]: " << 1000.0 * clock() / CLOCKS_PER_SEC << " ms.\n";
    #endif
    return 0;
}

Compilation message (stderr)

bitaro.cpp: In function 'int32_t main()':
bitaro.cpp:124:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  124 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
bitaro.cpp:125:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  125 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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