Submission #1221548

#	Time	Username	Problem	Language	Result	Execution time	Memory
1221548		steveonalex	Hack (APIO25_hack)	C++20	75.70 / 100	83 ms	1684 KiB

hack

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef unsigned int ul;
typedef unsigned long long ull;
 
#define MASK(i) (1ULL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
#define ALL(v) (v).begin(), (v).end()
 
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
ll gcd(ll a, ll b){return __gcd(abs(a), abs(b));}
ll lcm(ll a, ll b){return abs(a) / gcd(a, b) * abs(b);}
 
ll LASTBIT(ll mask){return (mask) & (-mask);}
int pop_cnt(ull mask){return __builtin_popcountll(mask);}
int ctz(ull mask){return __builtin_ctzll(mask);}
int logOf(ull mask){return 63 - __builtin_clzll(mask);}
 
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rngesus(ll l, ll r){return l + (ull) rng() % (r - l + 1);}
 
template <class T1, class T2>
    bool maximize(T1 &a, T2 b){
        if (a < b) {a = b; return true;}
        return false;
    }
 
template <class T1, class T2>
    bool minimize(T1 &a, T2 b){
        if (a > b) {a = b; return true;}
        return false;
    }
 
template <class T>
    void printArr(T container, string separator = " ", string finish = "\n", ostream &out = cout){
        for(auto item: container) out << item << separator;
        out << finish;
    }

template <class T>
    void remove_dup(vector<T> &a){
        sort(ALL(a));
        a.resize(unique(ALL(a)) - a.begin());
    }

#include "hack.h"

int get_collision(vector<ll> x){
    for(auto &i: x) i++;
    return collisions(x);
}

int find_dih(int x){
    vector<int> divisor;
    for(int i = 1; i * i <= x; ++i) {
        if (x % i == 0){
            divisor.push_back(i);
            divisor.push_back(x / i);
        }
    }

    remove_dup(divisor);

    for(int i: divisor) if (get_collision({0, i})) return i;

    return -1;
}

vector<ll> make_arr(int s, int len, int step){
    vector<ll> cur;
    for(int i = 0; i < len; ++i) cur.push_back(s + i * step);

    return cur;
}

int find_lesser_mod(){
    const int MOD = 179;
    vector<ll> first_shot;
    for(int i = 0; i < MOD; ++i) first_shot.push_back(i);
    for(int i = 1; i < MOD; ++i) first_shot.push_back(i * MOD);

    if (get_collision(first_shot) == 0) return -1; 


    if (get_collision(make_arr(0, MOD+1, 1))){
        int l = 1, r = MOD;
        while(l < r){
            int mid = (l + r) >> 1;
            vector<ll> cur; cur.push_back(0);
            for(int i = l; i <= mid; ++i) cur.push_back(i);

            if (get_collision(cur)) r = mid;
            else l = mid + 1;
        }
        return find_dih(l);
    }

    if (get_collision(make_arr(0, MOD+1, MOD))){
        int l = 1, r = MOD;
        while(l < r){
            int mid = (l + r) >> 1;
            vector<ll> cur; cur.push_back(0);
            for(int i = l; i <= mid; ++i) cur.push_back(i * MOD);

            if (get_collision(cur)) r = mid;
            else l = mid + 1;
        }
        return find_dih(l * MOD);
    }

    int l1 = 0, r1 = MOD-1;
    int l2 = 1, r2 = MOD;
    while(l1 < r1 || l2 < r2){
        if (r2 - l2 > r1 - l1){
            int mid = (l2 + r2) >> 1;
            vector<ll> cur;
            for(int i = l1; i <= r1; ++i) cur.push_back(i);
            for(int i = l2; i <= mid; ++i) cur.push_back(i * MOD);

            if (get_collision(cur)) r2 = mid;
            else l2 = mid + 1;
        }
        else{
            int mid = (l1 + r1) >> 1;
            vector<ll> cur;
            for(int i = l1; i <= mid; ++i) cur.push_back(i);
            for(int i = l2; i <= r2; ++i) cur.push_back(i * MOD);

            if (get_collision(cur)) r1 = mid;
            else l1 = mid + 1;
        }
    }
    return find_dih(r2 * MOD - r1);
}

int hack(){
    const int MOD = 31627;
    int less_mod = find_lesser_mod();
    if (less_mod != -1) return less_mod;

    int l1 = 0, r1 = MOD-1;
    int l2 = 1, r2 = MOD;
    while(l1 < r1 || l2 < r2){
        if (r2 - l2 > r1 - l1){
            int mid = (l2 + r2) >> 1;
            vector<ll> cur;
            for(int i = l1; i <= r1; ++i) cur.push_back(i);
            for(int i = l2; i <= mid; ++i) cur.push_back(i * MOD);

            if (get_collision(cur)) r2 = mid;
            else l2 = mid + 1;
        }
        else{
            int mid = (l1 + r1) >> 1;
            vector<ll> cur;
            for(int i = l1; i <= mid; ++i) cur.push_back(i);
            for(int i = l2; i <= r2; ++i) cur.push_back(i * MOD);

            if (get_collision(cur)) r1 = mid;
            else l1 = mid + 1;
        }
    }
    return find_dih(r2 * MOD - r1);
}

• Subtask 0: 0 / 0
• Subtask 1: 8 / 8
• Subtask 2: 17 / 17
• Subtask 3: 50.6615 / 75