verify/yosupo/data-structure/fast-set/predecessor_problem.test.cpp

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• Last update: 2026-10-24 00:10:28+07:00
• Problem: https://judge.yosupo.jp/problem/predecessor_problem

Depends on

• data-structure/fast-set.hpp
• template.hpp

Code

#define PROBLEM "https://judge.yosupo.jp/problem/predecessor_problem"
#include "template.hpp"
#include "data-structure/fast-set.hpp"

int main(){
    cin.tie(nullptr)->sync_with_stdio(false);
    int n,q;
    cin >> n >> q;
    string t;
    cin >> t;
    FastSet fs(n);
    for(int i=0;i<n;i++)if(t[i]=='1')fs.insert(i);
    while(q--){
        int op,k;
        cin >> op >> k;
        if(op==0){
            fs.insert(k);
        }else if(op==1){
            fs.erase(k);
        }else if(op==2){
            cout << fs.count(k) << "\n";
        }else if(op==3){
            int x=fs.next(k);
            if(x==n)x=-1;
            cout << x << "\n";
        }else{
            cout << fs.prev(k) << "\n";
        }
    }
}

#line 1 "verify/yosupo/data-structure/fast-set/predecessor_problem.test.cpp"
#define PROBLEM "https://judge.yosupo.jp/problem/predecessor_problem"
#line 2 "template.hpp"
#include<bits/stdc++.h>

using namespace std;

using ll = long long;
using db = long double;
using i128 = __int128_t;
using u32 = uint32_t;
using u64 = uint64_t;
template<class T>
using PQ = priority_queue<T,vector<T>,greater<T>>;

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

#define ALL(a) a.begin(),a.end()
#define RALL(a) a.rbegin(),a.rend()
#define SZ(a) (int)(a.size())
#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 LB(a,x) (int)(lower_bound(ALL(a),x)-a.begin())
#define UB(a,x) (int)(upper_bound(ALL(a),x)-a.begin())
#define FIND(a,x) (int)(find(ALL(a),x)-a.begin())
#define COUNT(a,x) (int)count(ALL(a),x)
#define MIN(a) *min_element(ALL(a))
#define MAX(a) *max_element(ALL(a))

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>
T floor(T a,T b){return a/b-((a^b)<0&&a%b);}
template<class T>
T ceil(T a,T b){return a/b+((a^b)>=0&&a%b);}

int popcnt(ll x){return __builtin_popcountll(x);}
int topbit(ll x){return x==0?-1:63-__builtin_clzll(x);}
int lowbit(ll x){return x==0?-1:__builtin_ctzll(x);}

template<class T,class U>
T SUM(const U &a){return accumulate(ALL(a),T{});}
template<class T>
vector<int> argsort(const vector<T> &a){
    vector<int> p(SZ(a));
    iota(ALL(p),0);
    stable_sort(ALL(p),[&](int i,int j){return a[i]<a[j];});
    return p;
}

template<class T,size_t D=0>
struct VecBuilder{
    array<size_t,D> d;
    VecBuilder<T,D+1> operator[](size_t n)const{
        VecBuilder<T,D+1> res{};
        for(size_t i=0;i<D;i++)res.d[i]=d[i];
        res.d[D]=n;
        return res;
    }
    template<size_t I=0>
    auto build(const T &x)const{
        if constexpr(I+1==D)return vector<T>(d[I],x);
        else return vector<decltype(build<I+1>(x))>(d[I],build<I+1>(x));
    }
    auto operator()(const T &x=T())const{
        static_assert(D>0);
        return build(x);
    }
};
template<class T>
inline constexpr VecBuilder<T> VEC{};

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]);
    }
};
#line 4 "verify/yosupo/data-structure/fast-set/predecessor_problem.test.cpp"

int main(){
    cin.tie(nullptr)->sync_with_stdio(false);
    int n,q;
    cin >> n >> q;
    string t;
    cin >> t;
    FastSet fs(n);
    for(int i=0;i<n;i++)if(t[i]=='1')fs.insert(i);
    while(q--){
        int op,k;
        cin >> op >> k;
        if(op==0){
            fs.insert(k);
        }else if(op==1){
            fs.erase(k);
        }else if(op==2){
            cout << fs.count(k) << "\n";
        }else if(op==3){
            int x=fs.next(k);
            if(x==n)x=-1;
            cout << x << "\n";
        }else{
            cout << fs.prev(k) << "\n";
        }
    }
}

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