BZOJ 3223 FHQ_Treap平衡树

题目链接

题意：

给定一个长度为n的数组，初始为1,..,n，求经过m次反转操作后数组

思路：

FHQ_Treap平衡树操作

C++代码：

#include<map>
#include<set>
#include<stack>
#include<cmath>
#include<queue>
#include<vector>
#include<string>
#include<cstdio>
#include<cstring>
#include<complex>
#include<iostream>
#include<algorithm>
using namespace std;
#define ls ftr[k].l
#define rs ftr[k].r
typedef double DB;
typedef long long LL;
typedef complex<double>CD;
const int maxn = 100010;
const int mod = 1e9+7;
const int inf = 0x3f3f3f3f;

void Mod( int &x ){ x%=mod; }
int Min( int a , int b ){ return a<b?a:b; }
int Max( int a , int b ){ return a>b?a:b; }
int Random(){ static int seed = 703; return seed=(int)(seed*48271LL%2147483647); }

int sizes,root;

struct FHQ_Treap
{
    int l,r;
    int v,rnd;
    int sizes;
    int rev;
}ftr[maxn];

void Revone( int k )
{
    if ( !k )
        return;
    ftr[k].rev ^= 1;
    swap ( ls , rs );
}

void Push_up( int k )
{
    if ( !k )
        return;
    ftr[k].sizes = ftr[ls].sizes+ftr[rs].sizes+1;
}

void Push_down( int k )
{
    if ( !k )
        return;
    if ( ftr[k].rev )
        Revone( ls ),Revone( rs );
    ftr[k].rev = 0;
}

void Build ( int &k , int s )
{
    k = ++sizes;
    ftr[k].l = 0;
    ftr[k].r = 0;
    ftr[k].v = s;
    ftr[k].rnd = Random();
    ftr[k].sizes = 1;
    ftr[k].rev = 0;
}

void Split( int k , int &l , int &r , int s )
{
    if ( s==0 )
        l = 0,r = k;
    else if ( s==ftr[k].sizes )
        l = k,r = 0;
    else if ( s<=ftr[ls].sizes )
        Push_down( r=k ),Split( ls , l , ls , s ),Push_up( k );
    else
        Push_down( l=k ),Split( rs , rs , r , s-ftr[ls].sizes-1 ),Push_up( k );
}

void Merge( int &k , int l , int r )
{
    if ( l==0||r==0 )
        k = l+r;
    else if ( ftr[l].rnd<ftr[r].rnd )
        Push_down( k=l ),Merge( rs , rs , r ),Push_up( k );
    else
        Push_down( k=r ),Merge( ls , l , ls ),Push_up( k );
}

void Reverse( int l , int r )
{
    int x,y,z;
    Split( root , x , y , r );
    Split( x , z , x , l-1 );
    Revone ( x );
    Merge( x , z , x );
    Merge( root , x , y );
}

int Find( int p )
{
    int x,y,z,ans;
    Split( root , x , y , p );
    Split( x , z , x , p-1 );
    ans = ftr[x].v;
    Merge( x , z , x );
    Merge( root , x , y );
    return ans;
}

int main()
{
    for ( int n,m ; scanf( "%d%d" , &n ,&m )==2 ; )
    {
        sizes = root = 0;
        for ( int i=1,t ; i<=n ; i++ )
            Build( t , i ),Merge( root , root , t );
        for ( int i=1,l,r ; i<=m ; i++ )
            scanf ( "%d%d" , &l , &r ),Reverse( l , r );
        for ( int i=1 ; i<=n ; i++ )
            printf ( "%d " , Find(i) );
        printf ( "\n" );
    }
    return 0;
}