Submission #483043

#	Time	Username	Problem	Language	Result	Execution time	Memory
483043		jalsol	Bosses (BOI16_bosses)	C++17	100 / 100	1243 ms	716 KiB

bosses

#ifdef LOCAL
#include "local.h"
#else
#include <bits/stdc++.h>
#define debug(...)
#define DB(...)
#endif

using namespace std;

const bool __initialization = []() {
    cin.tie(nullptr)->sync_with_stdio(false);
#define TASK "empty"
    if (fopen(TASK".inp", "r")) {
        (void)(!freopen(TASK".inp", "r", stdin));
        (void)(!freopen(TASK".out", "w", stdout)); }
    cout << setprecision(12) << fixed;
    return true;
}();

using ll = long long;
using ld = long double;

#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()

#define For(i, l, r) for (int i = (l); i <= (r); ++i)
#define Ford(i, r, l) for (int i = (r); i >= (l); --i)
#define Rep(i, n) For (i, 0, (n) - 1)
#define Repd(i, n) Ford (i, (n) - 1, 0)
#define Fe(...) for (auto __VA_ARGS__)

template <class C> inline int isz(const C& c) { return static_cast<int>(c.size()); }
template <class T> inline bool chmin(T& a, const T& b) { return (a > b) ? a = b, true : false; }
template <class T> inline bool chmax(T& a, const T& b) { return (a < b) ? a = b, true : false; }

constexpr ld eps = 1e-9;
constexpr int inf = 1e9;
constexpr ll linf = 1e18;

// =============================================================================

constexpr int maxn = 5000 + 5;

int n;
vector<int> g[maxn];

queue<int> q;
int pre[maxn];

void Bfs(int src) {
    memset(pre + 1, 0, sizeof(int) * n);
    q.push(src);
    pre[src] = -1;

    while (isz(q)) {
        int u = q.front(); q.pop();

        Fe (v : g[u]) {
            if (!pre[v]) {
                pre[v] = u;
                q.push(v);
            }
        }
    }
}

int sz[maxn];

void Dfs(int u) {
    sz[u] = 1;

    Fe (v : g[u]) {
        if (pre[v] == u) {
            Dfs(v);
            sz[u] += sz[v];
        }
    }
}

signed main() {
    cin >> n;

    For (i, 1, n) {
        int ne; cin >> ne;
        Rep (_, ne) {
            int x; cin >> x;
            g[x].push_back(i);
        }
    }

    ll ans = inf;

    For (i, 1, n) {
        Bfs(i);
        memset(sz + 1, 0, sizeof(int) * n);
        Dfs(i);

        if (count(pre + 1, pre + n + 1, 0)) continue;

        ll sum = accumulate(sz + 1, sz + n + 1, 0LL);
        chmin(ans, sum);
    }

    cout << ans << '\n';
}

// this can't be right...

• Subtask 1: 22 / 22
• Subtask 2: 45 / 45
• Subtask 3: 33 / 33