Submission #933755

#	Time	Username	Problem	Language	Result	Execution time	Memory
933755		LucaIlie	Political Development (BOI17_politicaldevelopment)	C++17	100 / 100	2087 ms	29044 KiB

politicaldevelopment

#include <bits/stdc++.h>

using namespace std;

struct pv {
    int u, a;

    bool operator < ( const pv &x ) const {
        if ( a == x.a )
            return u < x.u;
        return a < x.a;
    }
};

const int MAX_N = 5e4;
const int MAX_K = 10;
int perm[MAX_N], pos[MAX_N];
unordered_set<int> adj[MAX_N];
set<pv> vertMinSize;

int solve( vector<int> vertices ) {
    int n = vertices.size();
    for ( int i = 0; i < n; i++ )
        pos[vertices[i]] = i;

    int ans = 0;
    for ( int mask = 0; mask < (1 << n); mask++ ) {
        vector<int> v;
        for ( int i = 0; i < n; i++ ) {
            if ( (mask >> i) & 1)
                v.push_back( vertices[i] );
        }

        bool ok = true;
        for ( int x: v ) {
            for ( int y: v ) {
                if ( x != y && adj[x].find( y ) == adj[x].end() )
                    ok = false;
            }
        }

        if ( ok )
            ans = max( ans, (int)v.size() );
    }

    for ( int i = 0; i < n; i++ )
        pos[vertices[i]] = -1;

    return ans;
}

int main() {
    int n, k, minn = n;

    cin >> n >> k;
    for ( int u = 0; u < n; u++ ) {
        int d;
        cin >> d;
        for ( int j = 0; j < d; j++ ) {
            int v;
            cin >> v;
            adj[u].insert( v );
        }
        minn = min( minn, d );
        vertMinSize.insert( { u, d } );
    }
    for ( int i = 0; i < n; i++ )
        pos[i] = -1;

    if ( minn > k )
        exit( 1 );

    int ans = 0;
    for ( int i = 0; i < n; i++ ) {
        int u = vertMinSize.begin()->u;

        vector<int> vertices;
        vertices.push_back( u );
        for ( int v: adj[u] )
            vertices.push_back( v );
        ans = max( ans, solve( vertices ) );

        for ( int v: adj[u] ) {
            vertMinSize.erase( { v, (int)adj[v].size() } );
            adj[v].erase( u );
            vertMinSize.insert( { v, (int)adj[v].size() } );
        }
        vertMinSize.erase( { u, (int)adj[u].size() } );
        adj[u].clear();
    }

    cout << ans;

    return 0;
}

Compilation message (stderr)

politicaldevelopment.cpp: In function 'int main()':
politicaldevelopment.cpp:53:15: warning: 'n' is used uninitialized in this function [-Wuninitialized]
   53 |     int n, k, minn = n;
      |               ^~~~

• Subtask 1: 4 / 4
• Subtask 2: 12 / 12
• Subtask 3: 23 / 23
• Subtask 4: 38 / 38
• Subtask 5: 23 / 23