data-structure/fast-set.hpp

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• Last update: 2026-04-16 02:00:18+07:00
• Include: #include "data-structure/fast-set.hpp"

Depends on

• template.hpp

Verified with

• verify/yosupo/data-structure/predecessor_problem.test.cpp

Code

#pragma once
#include "template.hpp"

/**
 * Author: Teetat T.
 * Date: 2026-04-16
 * Description: Fast Set
 */

struct FastSet{
    using u64 = uint64_t;

    int n,len;
    vector<u64> t;

    FastSet(){}
    FastSet(int n){build(n);}

    int size(){return n;}
    void build(int _n){
        assert(_n>=0);
        n=_n;
        len=1;
        while((len<<6)<n)len<<=6;
        len/=63;
        t.resize(len+(n+63)/64);
    }

    bool count(int i)const{
        assert(0<=i&&i<n);
        return t[len+(i>>6)]>>(i&63)&1;
    }
    void insert(int x){
        assert(0<=x&&x<n);
        int i=len+(x>>6),j=x&63;
        while(true){
            if(t[i]>>j&1ULL)return;
            t[i]|=1ULL<<j;
            if(!i)return;
            j=(--i)&63;
            i>>=6;
        }
    }
    void erase(int x){
        assert(0<=x&&x<n);
        int i=len+(x>>6),j=x&63;
        while(true){
            t[i]&=~(1ULL<<j);
            if(!i||t[i])return;
            j=(--i)&63;
            i>>=6;
        }
    }
    int next(int x){
        if(x>=n)return n;
        if(x<0)x=0;
        if(count(x))return x;
        int i=len+(x>>6),j=x&63;
        while(true){
            if(t[i]&((~1ULL)<<j)){
                j=__builtin_ctzll(t[i]&((~1ULL)<<j));
                if(i>=len)return (i-len)*64+j;
                break;
            }
            if(!i)return n;
            j=(--i)&63;
            i>>=6;
        }
        i=i*64+j+1;
        while(i<len)i=i*64+__builtin_ctzll(t[i])+1;
        return (i-len)*64+__builtin_ctzll(t[i]);
    }
    int prev(int x){
        if(x<0)return -1;
        if(x>=n)x=n-1;
        if(count(x))return x;
        int i=len+(x>>6),j=x&63;
        while(true){
            if(t[i]&((1ULL<<j)-1ULL)){
                j=63-__builtin_clzll(t[i]&((1ULL<<j)-1ULL));
                if(i>=len)return (i-len)*64+j;
                break;
            }
            if(!i)return -1;
            j=(--i)&63;
            i>>=6;
        }
        i=i*64+j+1;
        while(i<len)i=i*64+64-__builtin_clzll(t[i]);
        return (i-len)*64+63-__builtin_clzll(t[i]);
    }
};

#line 2 "template.hpp"
#include<bits/stdc++.h>

using namespace std;

#define pb push_back
#define eb emplace_back
#define mp make_pair
#define mt make_tuple
#define fi first
#define se second

#define ALL(a) a.begin(),a.end()
#define RALL(a) a.rbegin(),a.rend()
#define SORT(a) sort(ALL(a))
#define RSORT(a) sort(RALL(a))
#define REV(a) reverse(ALL(a))
#define UNI(a) a.erase(unique(ALL(a)),a.end())
#define SZ(a) (int)(a.size())
#define LB(a,x) (int)(lower_bound(ALL(a),x)-a.begin())
#define UB(a,x) (int)(upper_bound(ALL(a),x)-a.begin())
#define MIN(a) *min_element(ALL(a))
#define MAX(a) *max_element(ALL(a))

using ll = long long;
using db = long double;
using i128 = __int128_t;
using u32 = uint32_t;
using u64 = uint64_t;

const int INF=INT_MAX/2;
const ll LINF=LLONG_MAX/4;
const db DINF=numeric_limits<db>::infinity();
const int MOD=998244353;
const int MOD2=1000000007;
const db EPS=1e-9;
const db PI=acos(db(-1));

template<class T>
using PQ = priority_queue<T,vector<T>,greater<T>>;

#define vv(T,a,n,...) vector<vector<T>> a(n,vector<T>(__VA_ARGS__))
#define vvv(T,a,n,m,...) vector<vector<vector<T>>> a(n,vector<vector<T>>(m,vector<T>(__VA_ARGS__)))
#define vvvv(T,a,n,m,k,...) vector<vector<vector<vector<T>>>> a(n,vector<vector<vector<T>>>(m,vector<vector<T>>(k,vector<T>(__VA_ARGS__))))

template<class T,class U>
bool chmin(T &a,U b){return b<a?a=b,1:0;}
template<class T,class U>
bool chmax(T &a,U b){return a<b?a=b,1:0;}
template<class T,class U>
T SUM(const U &a){return accumulate(ALL(a),T{});}

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng64(chrono::steady_clock::now().time_since_epoch().count());
#line 3 "data-structure/fast-set.hpp"

/**
 * Author: Teetat T.
 * Date: 2026-04-16
 * Description: Fast Set
 */

struct FastSet{
    using u64 = uint64_t;

    int n,len;
    vector<u64> t;

    FastSet(){}
    FastSet(int n){build(n);}

    int size(){return n;}
    void build(int _n){
        assert(_n>=0);
        n=_n;
        len=1;
        while((len<<6)<n)len<<=6;
        len/=63;
        t.resize(len+(n+63)/64);
    }

    bool count(int i)const{
        assert(0<=i&&i<n);
        return t[len+(i>>6)]>>(i&63)&1;
    }
    void insert(int x){
        assert(0<=x&&x<n);
        int i=len+(x>>6),j=x&63;
        while(true){
            if(t[i]>>j&1ULL)return;
            t[i]|=1ULL<<j;
            if(!i)return;
            j=(--i)&63;
            i>>=6;
        }
    }
    void erase(int x){
        assert(0<=x&&x<n);
        int i=len+(x>>6),j=x&63;
        while(true){
            t[i]&=~(1ULL<<j);
            if(!i||t[i])return;
            j=(--i)&63;
            i>>=6;
        }
    }
    int next(int x){
        if(x>=n)return n;
        if(x<0)x=0;
        if(count(x))return x;
        int i=len+(x>>6),j=x&63;
        while(true){
            if(t[i]&((~1ULL)<<j)){
                j=__builtin_ctzll(t[i]&((~1ULL)<<j));
                if(i>=len)return (i-len)*64+j;
                break;
            }
            if(!i)return n;
            j=(--i)&63;
            i>>=6;
        }
        i=i*64+j+1;
        while(i<len)i=i*64+__builtin_ctzll(t[i])+1;
        return (i-len)*64+__builtin_ctzll(t[i]);
    }
    int prev(int x){
        if(x<0)return -1;
        if(x>=n)x=n-1;
        if(count(x))return x;
        int i=len+(x>>6),j=x&63;
        while(true){
            if(t[i]&((1ULL<<j)-1ULL)){
                j=63-__builtin_clzll(t[i]&((1ULL<<j)-1ULL));
                if(i>=len)return (i-len)*64+j;
                break;
            }
            if(!i)return -1;
            j=(--i)&63;
            i>>=6;
        }
        i=i*64+j+1;
        while(i<len)i=i*64+64-__builtin_clzll(t[i]);
        return (i-len)*64+63-__builtin_clzll(t[i]);
    }
};

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