Submission #1266056

#	Time	Username	Problem	Language	Result	Execution time	Memory
1266056		icebear	Bitaro’s Party (JOI18_bitaro)	C++20	100 / 100	943 ms	166424 KiB

bitaro

// ~~ icebear ~~
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int, int> ii;
typedef pair<int, ii> iii;

template<class T>
    bool minimize(T &a, const T &b) {
        if (a > b) return a = b, true;
        return false;
    }

template<class T>
    bool maximize(T &a, const T &b) {
        if (a < b) return a = b, true;
        return false;
    }

#define FOR(i,a,b) for(int i=(a); i<=(b); ++i)
#define FORR(i,a,b) for(int i=(a); i>=(b); --i)
#define REP(i, n) for(int i=0; i<(n); ++i)
#define RED(i, n) for(int i=(n)-1; i>=0; --i)
#define MASK(i) (1LL << (i))
#define BIT(S, i) (((S) >> (i)) & 1)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define task "icebear"

const int MOD = 1e9 + 7;
const int inf = 1e9 + 27092008;
const ll INF = 1e18 + 27092008;
const int N = 2e5 + 5;
const int S = 200;
int n, m, q;
ii dist[S][N], tmp[S];
vector<int> G[N];
int f[N];

void mergeDist(int u, int v) {
    int i = 0, j = 0, cur = 0;
    while(cur < S) {
        if (i < S && f[dist[i][u].se] > 0) {
            i++;
            continue;
        }
        if (j < S && f[dist[j][v].se] > 0) {
            j++;
            continue;
        }
        if (i < S && dist[i][u].se > 0 && (j == S || dist[i][u].fi > dist[j][v].fi + 1 || dist[j][v].se == 0)) {
            tmp[cur++] = dist[i][u];
            f[dist[i][u].se] = 1;
            i++;
        } else if (j < S && dist[j][v].se > 0) {
            tmp[cur++] = mp(dist[j][v].fi + 1, dist[j][v].se);
            f[dist[j][v].se] = 1;
            j++;
        } else break;
    }
    REP(i, cur) dist[i][u] = tmp[i], f[tmp[i].se] = 0;
    REP(i, S) f[dist[i][v].se] = 0;
}

void prepareDist() {
    FOR(i, 1, n) {
        dist[0][i] = mp(0, i);
        for(int v : G[i]) mergeDist(i, v);
    }
}

void init(void) {
    cin >> n >> m >> q;
    FOR(i, 1, m) {
        int u, v;
        cin >> u >> v;
        if (u < v) swap(u, v);
        G[u].pb(v);
    }
}

void process(void) {
    vector<bool> inQuery(n + 5, false);
    inQuery[0] = true;
    prepareDist();
    while(q--) {
        int T, k; cin >> T >> k;
        vector<int> nodes(k);
        for(int &i : nodes) cin >> i, inQuery[i] = true;
        bool haveAns = false;
        if (k < S) {
            REP(i, S) if (!inQuery[dist[i][T].se]) {
                cout << dist[i][T].fi << '\n';
                haveAns = true;
                break;
            }
        } else {
            FOR(i, 1, n) f[i] = 0;
            FOR(i, 1, T) {
                for(int v : G[i])
                    if (!inQuery[v] || (inQuery[v] && f[v] > 0))
                        maximize(f[i], f[v] + 1);
            }
            if (f[T] > 0 || !inQuery[T]) {
                cout << f[T] << '\n';
                haveAns = true;
            }
        }
        if (!haveAns) cout << -1 << '\n';
        for(int &i : nodes) inQuery[i] = false;
    }
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    int tc = 1;
//     cin >> tc;
    while(tc--) {
        init();
        process();
    }
    return 0;
}

Compilation message (stderr)

bitaro.cpp: In function 'int main()':
bitaro.cpp:122:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  122 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
bitaro.cpp:123:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  123 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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