Submission #1184800

#	Time	Username	Problem	Language	Result	Execution time	Memory
1184800		steveonalex	Colors (BOI20_colors)	C++20	67 / 100	0 ms	436 KiB

Colors

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
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());
mt19937_64 rng(1);
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());
    }

ll solve(ll n);

namespace InteractorLib{
    set<ll> S;
    ll last = 0;
    ll n, c;
    bool valid;

    int query(ll x){
        if (x < 1 || x > n) valid = false;
        if (S.insert(x).second == false){
            valid = false;
        }
        ll diff = abs(last - x);
        last = x;
        return diff >= c;
    }

    int grade(){
        n = rngesus(666532744850833408LL, 666532744850833408LL);
        c = rngesus(max(1, n - 100), n);

        cout << n << " " << c << "\n";

        S.clear(); last = 0;
        valid = true;
        
        ll ans = solve(n);

        if (valid == false) return 1;
        if (ans != c) return 2;
        if (S.size() > 64) return 3;
        return 0;
    }
};
// using namespace InteractorLib;

int query(ll x){
    if (x < 1) exit(1);
    cout << "? " << x << endl;
    int verdict; cin >> verdict;
    return verdict;
}

void update(pair<ll, ll> &p, ll x, bool verdict){
    if (verdict) minimize(p.second, x);
    else maximize(p.first, x + 1);
}

namespace Sub3{
    int solve(ll n){
        pair<ll, ll> ans = make_pair(1, n);
        ll last = n / 2 + 1;
        query(last);

        ll l = last, r = last;
        while(r - l + 1 < n){
            l = max(1, l - 32);
            int verdict = query(l);
            update(ans, abs(last - l), verdict);
            last = l;

            if (verdict) break;
            if (r - l + 1 == n) break;

            r = min(n, r + 32);
            verdict = query(r);
            update(ans, abs(last - r), verdict);
            last = r;

            if (verdict) break;
        }

        while(l <= r){
            if (ans.first == ans.second) break;
            if (last == l){
                r--;
                int verdict = query(r);
                update(ans, abs(last - r), verdict);
                last = r;
            }
            else{
                l++;
                int verdict = query(l);
                update(ans, abs(last - l), verdict);
                last = l;
            }
        }

        return ans.first;
    }
}

namespace Sub4{
    ll get_starting_point(ll n){
        pair<ll, ll> range = {0, 0};
        ll cur = 0;
        ll l = 1;
        while(l < n){
            ll mid = (l + n) >> 1;

            if (cur == range.first) cur += mid;
            else cur -= mid;
            minimize(range.first, cur);
            maximize(range.second, cur);

            l = mid + 1;
        }
        if (range.second - range.first + 1 != n) assert(false);
        return 1 - range.first;
    }

    ll solve(ll n){
        pair<ll, ll> ans = make_pair(1, n);
        ll last = get_starting_point(n);
        query(last);
        set<ll> S;

        while(ans.first < ans.second){
            ll mid = (ans.first + ans.second) / 2;

            ll query_point = -1;
            while(query_point == -1 && mid >= ans.first){
                if (last + mid <= n && S.find(last + mid) == S.end()) query_point = last + mid;
                else if (last - mid >= 1 && S.find(last - mid) == S.end()) query_point = last - mid;
                if (query_point != -1) break;
                mid--;
            }

            if (query_point == -1) break;
            int verdict = query(query_point);
            update(ans, abs(query_point - last), verdict);
            last = query_point;
            S.insert(last);
        }


        if (ans.first == ans.second) return ans.first;
        if (ans.second == ans.first + 1) {
            if (last - ans.first > 1 && S.find(last - ans.first) == S.end()){
                int verdict = query(last - ans.first);
                update(ans, ans.first, verdict);
                return ans.first;
            }
            if (last + ans.first <= n && S.find(last + ans.first) == S.end()){
                int verdict = query(last + ans.first);
                update(ans, ans.first, verdict);
                return ans.first;
            }
            
            for(int i = 1; i + ans.first <= n; ++i) {
                if (S.find(i) == S.end() && S.find(i + ans.first) == S.end()){
                    query(i);
                    int verdict = query(i + ans.first);
                    update(ans, ans.first, verdict);
                    return ans.first;
                }
            }
        }
        if (ans.first + 1 < ans.second){
            for(ll i = 1; i + ans.first <= n; ++i){
                ll l = i, r = i + ans.first;
                bool check = true;
                ll last = -1;
                while(true){
                    if (l < 1 || S.find(l) != S.end()){
                        check = false;
                        break;
                    }
                    if (last != -1 && abs(last - l) + 1 == ans.second) break;
                    last = l;
                    l--;
                    if (r > n || S.find(r) != S.end()){
                        check = false;
                        break;
                    }
                    if (abs(last - r) + 1 == ans.second) break;
                    last = r;
                    r++;
                }

                if (check == false) continue;

                l = i, r = i + ans.first;
                last = -1;
                while(ans.first < ans.second){
                    int verdict = query(l);
                    if (last != -1) update(ans, abs(last - l), verdict);
                    if (last != -1 && abs(last - l) + 1 >= ans.second) break;
                    last = l;
                    l--;

                    verdict = query(r);
                    update(ans, abs(last - r), verdict);
                    if (abs(last - r) + 1 >= ans.second) break;
                    last = r;
                    r++;
                }

                break;
            }
        }
        return ans.first;
    }
}

ll solve(ll n){
    if (n <= 1000) return Sub3::solve(n);
    return Sub4::solve(n);
}

int main(void){
    ios::sync_with_stdio(0);cin.tie(0); cout.tie(0);

    clock_t start = clock();

    // for(int t = 1; t <= 1000; ++t) {
    //     cout << "Test case: " << t << endl;

    //     int code = grade();
    //     if (code == 0) {
    //         cout << "Correct!" << endl;
    //     }
    //     else{
    //         cout << "Incorrect[" << code << "]!" << endl;
    //         break;
    //     }
    // }

    ll n; cin >> n;
    int ans = solve(n);
    cout << "= " << ans << endl;

    cerr << "Time elapsed: " << clock() - start << "ms!\n";
    return 0;
}

• Subtask 1: 9 / 9
• Subtask 2: 13 / 13
• Subtask 3: 21 / 21
• Subtask 4: 24 / 24
• Subtask 5: 0 / 33