「模板」可持久化 HFQ-Treap

老师用的是静态数组的写法，开了很多数组…

其实个人更倾向于 struct 或者用 class 封装起来。

但是鉴于太难打 好吧，是我懒得打。

然后就借鉴了老师的模板，写出了属于自己的 压行 风格。

代码见下：（注：题目是洛谷P3835）

#include<cstdio>
#include<cstdlib>

#define rep(i,__l,__r) for(int i=__l,i##_end_=__r;i<=i##_end_;++i)
#define fep(i,__l,__r) for(int i=__l,i##_end_=__r;i>=i##_end_;--i)
#define writc(a,b) fwrit(a),putchar(b)
#define mp(a,b) make_pair(a,b)
#define ft first
#define sd second
#define LL long long
#define ull unsigned long long
#define pii pair<int,int>
#define Endl putchar('\n')
// #define FILEOI

#ifdef FILEOI
    #define MAXBUFFERSIZE 500000
    inline char fgetc(){
        static char buf[MAXBUFFERSIZE+5],*p1=buf,*p2=buf;
        return p1==p2&&(p2=(p1=buf)+fread(buf,1,MAXBUFFERSIZE,stdin),p1==p2)?EOF:*p1++;
    }
    #undef MAXBUFFERSIZE
    #define cg (c=fgetc())
#else
    #define cg (c=getchar())
#endif
template<class T>inline void qread(T& x){
    char c;bool f=0;
    while(cg<'0'||'9'<c)f|=(c=='-');
    for(x=(c^48);'0'<=cg&&c<='9';x=(x<<1)+(x<<3)+(c^48));
    if(f)x=-x;
}
inline int qread(){
    int x=0;char c;bool f=0;
    while(cg<'0'||'9'<c)f|=(c=='-');
    for(x=(c^48);'0'<=cg&&c<='9';x=(x<<1)+(x<<3)+(c^48));
    return f?-x:x;
}
template<class T,class... Args>inline void qread(T& x,Args&... args){qread(x),qread(args...);}
template<class T>inline T Max(const T x,const T y){return x>y?x:y;}
template<class T>inline T Min(const T x,const T y){return x<y?x:y;}
template<class T>inline T fab(const T x){return x>0?x:-x;}
inline int gcd(const int a,const int b){return b?gcd(b,a%b):a;}
inline void getInv(int inv[],const int lim,const int MOD){
    inv[0]=inv[1]=1;for(int i=2;i<=lim;++i)inv[i]=1ll*inv[MOD%i]*(MOD-MOD/i)%MOD;
}
template<class T>void fwrit(const T x){
    if(x<0)return (void)(putchar('-'),fwrit(-x));
    if(x>9)fwrit(x/10);putchar(x%10^48);
}
inline LL mulMod(const LL a,const LL b,const LL mod){//long long multiplie_mod
    return ((a*b-(LL)((long double)a/mod*b+1e-8)*mod)%mod+mod)%mod;
}

const int MAXN=5e7;
const int INF=(1ll<<31)-1;

int ncnt;
int son[MAXN+5][2];
int keyof[MAXN+5];
int rd[MAXN+5];
int siz[MAXN+5];
int rt[MAXN+5];
int rcnt;
inline void pushup(const int p){
    siz[p]=siz[son[p][0]]+siz[son[p][1]]+1;
}
inline int newnode(const int key){
    ++ncnt;
    son[ncnt][0]=son[ncnt][1]=0;
    keyof[ncnt]=key;
    rd[ncnt]=rand();
    siz[ncnt]=1;
    return ncnt;
}

struct Pair{
    int ele[2];
    Pair(){ele[0]=ele[1]=0;}
    Pair(const int A,const int B){ele[0]=A,ele[1]=B;}
};

inline int cpyNode(const int p){
    ++ncnt;
    son[ncnt][0]=son[p][0];
    son[ncnt][1]=son[p][1];
    keyof[ncnt]=keyof[p];
    rd[ncnt]=rd[p];
    siz[ncnt]=siz[p];
    return ncnt;
}

Pair split(int p,const int key,const bool mode,const bool flg=0){
//mode=0 时为按 key 分裂
//mode=1 时为按 rank 分裂
    Pair ret=Pair(0,0);
    if(p){
        int d;
        if(!flg)p=cpyNode(p);
        if(mode)d=(siz[son[p][0]]+1<=key);
        else d=(keyof[p]<=key);
        if(mode && d)ret=split(son[p][d],key-siz[son[p][0]]-1,mode,flg);
        else ret=split(son[p][d],key,mode,flg);
        son[p][d]=ret.ele[d^1];
        pushup(p);
        ret.ele[d^1]=p;
    }
    return ret;
}
int unite(int r1,int r2,const bool flg=0){
    if(r1*r2==0)return r1|r2;
    if(rd[r1]<rd[r2]){
        if(!flg)r1=cpyNode(r1);
        son[r1][1]=unite(son[r1][1],r2,flg);
        return pushup(r1),r1;
    }
    else{
        if(!flg)r2=cpyNode(r2);
        son[r2][0]=unite(r1,son[r2][0],flg);
        return pushup(r2),r2;
    }
}

int inser(const int p,const int key){
    Pair tmp=split(p,key,0);
    return unite(unite(tmp.ele[0],newnode(key)),tmp.ele[1]);
}

int delet(const int p,const int key){
    Pair tmp0=split(p,key,0);
    Pair tmp1=split(tmp0.ele[0],key-1,0);
    return unite(tmp1.ele[0],tmp0.ele[1]);
}

int getRank(const int p,const int key){
    if(!p)return 1;
    if(keyof[p]>key)return getRank(son[p][0],key);
    if(keyof[p]<key)return siz[son[p][0]]+1+getRank(son[p][1],key);
    return siz[son[p][0]]+1;
}

int atRank(const int p,const int rk){
    if(!p)return -INF;
    if(siz[son[p][0]]>=rk)return atRank(son[p][0],rk);
    else if(siz[son[p][0]]+1<rk)return atRank(son[p][1],rk-siz[son[p][0]]-1);
    else return keyof[p];
}

int getPre(const int p,const int key){
    Pair tmp1=split(p,key-1,0,1);
    int tsiz=siz[tmp1.ele[0]]-1;
    Pair tmp0=split(tmp1.ele[0],tsiz,1,1);
    int ret=keyof[tmp0.ele[1]];
    tmp1.ele[0]=unite(tmp0.ele[0],tmp0.ele[1],1);
    unite(tmp1.ele[0],tmp1.ele[1],1);
    return ret;
}

int getSuf(const int p,const int key){
    Pair tmp0=split(p,key,0,1);
    Pair tmp1=split(tmp0.ele[1],1,1,1);
    int ret=keyof[tmp1.ele[0]];
    tmp0.ele[1]=unite(tmp1.ele[0],tmp1.ele[1],1);
    unite(tmp0.ele[0],tmp0.ele[1],1);
    return ret;
}

int N,v,opt,x;

signed main(){
#ifdef FILEOI
    freopen("file.in","r",stdin);
    freopen("file.out","w",stdout);
#endif
    srand(233);
    qread(N);
    rt[0]=inser(rt[0],-INF);
    rt[0]=inser(rt[0],INF);
    while(N--){
        qread(v,opt,x);
        rt[++rcnt]=rt[v];
        if(opt==1)rt[rcnt]=inser(rt[rcnt],x);
        else if(opt==2)rt[rcnt]=delet(rt[rcnt],x);
        else if(opt==3)writc(getRank(rt[rcnt],x)-1,'\n');
        else if(opt==4)writc(atRank(rt[rcnt],x+1),'\n');
        else if(opt==5)writc(getPre(rt[rcnt],x),'\n');
        else writc(getSuf(rt[rcnt],x),'\n');
    }
    return 0;
}