Submission #91792

#	Time	Username	Problem	Language	Result	Execution time	Memory
91792		Tieuphong	Bosses (BOI16_bosses)	C++11	100 / 100	742 ms	888 KiB

bosses

/***************************************************************************/
/**********************  LANG TU HAO HOA  **********************************/
/***************************************************************************/
#include <bits/stdc++.h>
#define FOR(i, a, b) for (int i = (a); i <= (b); ++i)
#define FORD(i, a, b) for (int i = (a); i >= (b); --i)
#define pii pair<int, int>
#define sz(x) ((int) x.size())
#define PB push_back
#define PF push_front
#define MP make_pair
#define ll long long
#define F first
#define S second
#define maxc 1000000007
#define MOD 1000000007
#define base 107
#define eps 1e-6
#define pi acos(-1)
#define N 5003
#define K 10004
#define task ""
#define remain(x) ((x > MOD) ? (x - MOD) : x)

using namespace std;

int n, f[N], cnt = 0, in[N], ans = maxc;

pii canh[K];

vector <int> ke[N];

void DFS(int u)
{
    f[u] = 1;
    for (auto v : ke[u])
    {
        DFS(v);
        f[u] += f[v];
    }
}

void Sub1()
{
    int res = maxc;
    int Last = (1 << cnt) - 1;
    FOR(x, 0, Last)
    {
        if (__builtin_popcount(x) != n-1) continue;
        FOR(i, 1, n) ke[i].clear(), in[i] = 0, f[i] = 0;
        FOR(i, 1, cnt)
        {
            if ((x >> (i-1)) & 1)
            {
                ke[canh[i].F].PB(canh[i].S);
                in[canh[i].S]++;
            }
        }
        int root, sl = 0;
        FOR(i, 1, n)
        {
            if (!in[i])
            {
                root = i;
                sl++;
            }
        }
        if (sl > 1) continue;
        DFS(root);
        if (*min_element(f+1, f+n+1) == 0) continue;
        res = min(res, accumulate(f+1, f+n+1, 0));
    }
    cout << res;
    exit(0);
}

void Try(int root)
{
    fill(f+1, f+n+1, 0);
    int res = 0;
    queue <pii> q;
    q.push(MP(root, 1));
    while (!q.empty())
    {
        int u = q.front().F;
        int curH = q.front().S;
        q.pop();
        if (f[u]) continue;
        f[u] = 1;
        res += curH;
        for (auto v : ke[u])
        {
            if (f[v]) continue;
            q.push(MP(v, curH+1));
        }
    }
    if (accumulate(f+1, f+n+1, 0) == n) ans = min(res, ans);
}

int main()
{
    ios_base::sync_with_stdio(0); cin.tie(NULL); cout.tie(NULL);
    //freopen(task".inp", "r", stdin);
    //freopen(task".out", "w", stdout);
    cin >> n;
    FOR(i, 1, n)
    {
        int k; cin >> k;
        FOR(j, 1, k)
        {
            int x; cin >> x;
            canh[++cnt] = MP(x, i);
        }
    }
    if (n <= 10) Sub1();
    FOR(i, 1, cnt) ke[canh[i].F].PB(canh[i].S);
    FOR(i, 1, n) Try(i);
    cout << ans;
    return 0;
}

Compilation message (stderr)

bosses.cpp: In function 'void Sub1()':
bosses.cpp:69:12: warning: 'root' may be used uninitialized in this function [-Wmaybe-uninitialized]
         DFS(root);
         ~~~^~~~~~

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