BZOJ-2002: [Hnoi2010]Bounce 弹飞绵羊(Link-cut-tree)

题目：http://www.lydsy.com/JudgeOnline/problem.php?id=2002

每个点只会跳到另外一个确切的点，这跟树中每个节点只有一个父节点一样的，那么按照这个规律建树即可，然后LCT维护，对于每个查询，ACCESS(V)，然后输出sizeleft[v]即可。

代码：

472309f790529822e608a4b3d5ca7bcb0a46d483.jpg.png

# include 
# include 
# include 
 
using namespace std ;
 
# define MAXN 200010
# define L( t ) left[ t ]
# define R( t ) right[ t ]
# define F( t ) father[ t ]
# define G( t )F(F( t ) )
# define S( t ) size[ t ]
# define P( t ) parent[path_roof( t ) ]
# define update( t )S( t ) =S(L( t ) ) +S(R( t ) ) + 1
# define C( t ) (L(F( t ) ) == t )
# define clear( t )memset( t , 0 , sizeof( t ) )
 
int left[ MAXN ] , right[ MAXN ] , father[ MAXN ] , parent[ MAXN ] , size[ MAXN ] ;
 
void zag( int t ) {
    int k =R( t ) , u =F( t ) ;
    bool flag =C( t ) ;
    R( t ) =L( k ) ;F(L( k ) ) = t ;update( t ) ;
    L( k ) = t ;F( t ) = k ;           update( k ) ;
    F( k ) = u ; if ( u ) if ( flag )L( u ) = k ; else R( u ) = k ;
}
 
void zig( int t ) {
    int k =L( t ) , u =F( t ) ; 
    bool flag =C( t ) ;
    L( t ) =R( k ) ;F(R( k ) ) = t;update( t ) ;
    R( k ) = t ;F( t ) = k ;          update( k ) ;
    F( k ) = u ; if ( u ) if ( flag )L( u ) = k ; else R( u ) = k ;
}
 
void splay( int t ) {
    while (F( t ) ) {
        if ( !G( t ) ) if (C( t ) )zig(F( t ) ) ; else zag(F( t ) ) 
        ; else {
            if (C( t ) ) {
                if (C(F( t ) ) )zig(G( t ) ) ;
                zig(F( t ) ) ;
            } else {
                if ( !C(F( t ) ) )zag(G( t ) ) ;
                zag(F( t ) ) ;
            }
        }
    }
}
 
int path_roof( int t ) {
    splay( t ) ;
    while (L( t ) ) t =L( t ) ;
    return t ;
}
 
void Access( int t ) {
    int v = 0 ;
    do {
        splay( t ) ;
        F(R( t ) ) = 0 ;P(R( t ) ) = t ;R( t ) = v ;F( v ) = t ;update( t ) ;
        v = t ; t =P( t ) ;
    } while ( t ) ;
}
 
void Make_tree( int t ) {
    L( t ) =R( t ) =F( t ) = parent[ t ] = 0 ;
    S( t ) = 1 ;
}
 
void Cut( int t ) {
    Access( t ) ;splay( t ) ;
    F(L( t ) ) = 0 ;L( t ) = 0 ;P( t ) = 0 ;update( t ) ;
}
 
void Join( int t , int v ) {
    P( t ) = v ; 
    Access( t ) ;
}
 
void Init(  ) {
    F( 0 ) =L( 0 ) =R( 0 ) =S( 0 ) = 0;
    clear( parent ) ;
}
 
int k[ MAXN ] , n , m ;
 
int main (  ) {
    Init(  ) ; 
    scanf( "%d" , &n ) ;
    for ( int i = 0 ; i ++ < n + 1 ; )Make_tree( i ) ;
    for ( int i = 0 ; i ++ < n ; ) {
        scanf( "%d" , &k[ i ] ) ;
        Join( i ,min( n + 1 , i + k[ i ] ) ) ;
    }
    scanf( "%d" , &m ) ;
    while ( m -- ) {
        int x ;
        scanf( "%d" , &x ) ;
        if ( x == 1 ) {
            int y ;
            scanf( "%d" , &y ) ; y ++ ;
            Access( y ) ;splay( y ) ;
            printf( "%d\n" ,S(L( y ) ) ) ;
        } else {
            int y , z ;
            scanf( "%d%d" , &y , &z ) ; y ++ ;
            Cut( y ) ;Join( y ,min( y + z , n + 1 ) ) ;
        }
    }
    return 0 ;
}