Submission #631776

#	Time	Username	Problem	Language	Result	Execution time	Memory
631776		mdn2002	Jail (JOI22_jail)	C++14	21 / 100	77 ms	19356 KiB

jail

#include<bits/stdc++.h>
using namespace std;
int n , m , st [200005][21] , dp [200005] , s [200005] , t [200005] , aaa [200005] , vis [200005] , ff;
vector < int > gr [200005] , grr [200005] , ss [200005] , tt [200005];
void dfs ( int x , int p )
{
    dp [x] = dp [p] + 1;
    st [x][0] = p;
    for ( auto u : gr [x] )
    {
        if ( u == p ) continue;
        dfs ( u , x );
    }
}
void go ( int x , int p )
{
    aaa [x] = aaa [p];
    if ( ss [x] . size () || tt [x] . size () ) aaa [x] = x;
    for ( auto u : gr [x] )
    {
        if ( u == p ) continue;
        go ( u , x );
    }
}
void dfss ( int x )
{
    vis [x] = 1;
    for ( auto u : grr [x] )
    {
        if ( vis [u] == 1 )
        {
            ff = 1;
            continue;
        }
        else if ( vis [u] == 2 ) continue;
        else dfss ( u );
    }
    vis [x] = 2;
}
int lca ( int x , int y )
{
    if ( dp [x] > dp [y] ) swap ( x , y );
    int dif = dp [y] - dp [x];
    for ( int i = 0 ; i <= 20 ; i ++ )
    {
        if ( ( dif & ( 1 << i ) ) ) y = st [y][i];
    }
    if ( x == y ) return x;
    for ( int i = 20 ; i >= 0 ; i -- )
    {
        if ( st [x][i] != st [y][i] )
        {
            x = st [x][i];
            y = st [y][i];
        }
    }
    return st [x][0];
}
int inbet ( int x , int y , int z )
{
    if ( dp [z] > dp [x] && dp [z] > dp [y] ) return 0;
    int aa = lca ( x , y );
    if ( dp [aa] > dp [z] ) return 0;
    int a = lca ( x , z );
    int b = lca ( y , z );
    if ( a == z || b == z ) return 1;
    return 0;
}
int main()
{
    int q;
    cin >> q;
    while ( q -- )
    {
        ff = 0;
        cin >> n;
        for ( int i = 1 ; i <= n ; i ++ )
        {
            gr [i] . clear ();
            grr [i] . clear ();
            ss [i] . clear ();
            tt [i] . clear ();
            dp [i] = 0;
            vis [i] = 0;
            aaa [i] = 0;
            for ( int j = 0 ; j <= 20 ; j ++ ) st [i][j] = 0;
        }
        for ( int i = 0 ; i < n - 1 ; i ++ )
        {
            int x , y;
            cin >> x >> y;
            gr [x] . push_back ( y );
            gr [y] . push_back ( x );
        }
        dfs ( 1 , 0 );
        for ( int i = 1 ; i <= 20 ; i ++ )
        {
            for ( int j = 1 ; j <= n ; j ++ ) st [j][i] = st [ st [j][ i - 1 ] ][ i - 1 ];
        }
        cin >> m;
        long long sum = 0;
        for ( int i = 1 ; i <= m ; i ++ )
        {
            cin >> s [i] >> t [i];
            ss [ s [i] ] . push_back ( i );
            tt [ t [i] ] . push_back ( i );
            int a = lca ( s [i] , t [i] );
        }
        go ( 1 , 0 );
        int num = 0;
        for ( int i = 1 ; i <= m ; i ++ )
        {
            int x = s [i] , y = t [i] , z = lca ( x , y );
            while ( true )
            {
                if ( dp [x] < dp [z] ) break;
                if ( ss [x] . size () )
                {
                    if ( ss [x][0] != i )
                    {
                        grr [i] . push_back ( ss [x][0] );
                        num ++;
                    }
                }
                if ( tt [x] . size () )
                {
                    if ( tt [x][0] != i )
                    {
                        grr [ tt [x][0] ] . push_back ( i );
                        num ++;
                    }
                }
                if ( num > 10 * m ) break;
                if ( x == z ) break;
                x = aaa [ st [x][0] ];
            }
            x = t [i];
            while ( true )
            {
                if ( dp [x] < dp [z] ) break;
                if ( ss [x] . size () )
                {
                    if ( ss [x][0] != i )
                    {
                        grr [i] . push_back ( ss [x][0] );
                        num ++;
                    }
                }
                if ( tt [x] . size () )
                {
                    if ( tt [x][0] != i )
                    {
                        grr [ tt [x][0] ] . push_back ( i );
                        num ++;
                    }
                }
                if ( num > 10 * m ) break;
                if ( x == z ) break;
                x = aaa [ st [x][0] ];
            }
        }
        if ( num > 10 * m ) 
        {
            cout << "No" << endl;
            continue;
        }
        for ( int i = 1 ; i <= m ; i ++ )
        {
            if ( vis [i] == 0 ) dfss ( i );
        }
        if ( ff ) cout << "No" << endl;
        else cout << "Yes" << endl;
    }
}

/*
1
4
1 2
2 3
3 4
2
1 3
4 2
*/

Compilation message (stderr)

jail.cpp: In function 'int main()':
jail.cpp:107:17: warning: unused variable 'a' [-Wunused-variable]
  107 |             int a = lca ( s [i] , t [i] );
      |                 ^
jail.cpp:101:19: warning: unused variable 'sum' [-Wunused-variable]
  101 |         long long sum = 0;
      |                   ^~~

• Subtask 1: 0 / 5
• Subtask 2: 5 / 5
• Subtask 3: 16 / 16
• Subtask 4: 0 / 28
• Subtask 5: 0 / 12
• Subtask 6: 0 / 11
• Subtask 7: 0 / 23