Submission #337870

#	Time	Username	Problem	Language	Result	Execution time	Memory
337870		theshadow_04	Bosses (BOI16_bosses)	C++14	22 / 100	34 ms	2668 KiB

bosses

#include <bits/stdc++.h>
#define Task "BOSSES"
#define pb push_back
#define F first
#define S second

using namespace std;

const int maxn = 100005;

int n, cnt = 0;
vector<int> ke[maxn];
int f[maxn], In[maxn], ans = 2e9;
pair<int, int> ed[maxn];

void DFS(int u) {
    int sum = 0;
    for(auto v : ke[u]) {
        if(!f[v]) {
            DFS(v);
            sum += f[v];
        }
    }
    f[u] = sum + 1;
}

void Solve(int mask) {
    for(int i = 1; i <= n; ++ i) f[i] = 0, ke[i].clear(), In[i] = 0;
    for(int i = 1; i <= cnt; ++ i) {
        if((mask >> (i - 1)) & 1) ke[ed[i].F].pb(ed[i].S), In[ed[i].S] = 1;
    }
    int root = 0;
    for(int i = 1; i <= n; ++ i) {
        if(!In[i]) {
            if(root) return;
            root = i;
        }
    }
    DFS(root);
    int total = 0;
    for(int i = 1; i <= n; ++ i) {
        if(!f[i]) return;
        total += f[i];
    }
    ans = min(ans, total);
}

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);
    }
    cin >> n;
    for(int i = 1; i <= n; ++ i) {
        int k; cin >> k;
        while(k --) {
            int x; cin >> x;
            ed[++ cnt] = {x, i};
        }
    }

    for(int mask = 1; mask < (1 << cnt); ++ mask) {
        if(__builtin_popcount(mask) != n - 1) continue;
        Solve(mask);
    }

    cout << ans;
}

Compilation message (stderr)

bosses.cpp: In function 'int main()':
bosses.cpp:52:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   52 |         freopen(Task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
bosses.cpp:53:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   53 |         freopen(Task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 22 / 22
• Subtask 2: 0 / 45
• Subtask 3: 0 / 33