Submission #255072

#	Time	Username	Problem	Language	Result	Execution time	Memory
255072		davitmarg	Colors (BOI20_colors)	C++17	0 / 100	0 ms	384 KiB

Colors

/*
DavitMarg
In a honky-tonk,
Down in Mexico
*/
#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <string>
#include <cstring>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <queue>
#include <iomanip>
#include <bitset>
#include <stack>
#include <cassert>
#include <iterator>
#include <fstream>
#define mod 1000000007ll
#define LL long long
#define LD long double
#define MP make_pair
#define PB push_back
#define all(v) v.begin(), v.end()
#define fastIO ios::sync_with_stdio(false); cin.tie(0)
using namespace std;

const int N = 200005;

LL n, ans;
LL last;

unordered_map<LL, int> used;

int get(LL p)
{
    assert(!used[p]);
    used[p] = 1;
    cout << "? " << p << endl;
    int res;
    cin >> res;
    if (last && res && abs(last - p) < ans)
        ans = abs(last - p);
    last = p;
    return res;
}


LL f(LL x)
{
    LL i = n - x;
    return 1ll + i / 2ll;
}

void solve()
{
    last = 0;
    used.clear();
    cin >> n;
    ans = n;

    LL l = 1, r = n / 2 - (LL)(n % 2 == 0);
    while (l <= r)
    {
        LL m = (l + r) / 2;
        LL a = f(m + m), b = f(m + m) + m + m;
        /*if (rand() % 2)
            swap(a, b);*/
        get(a);
        if (get(b))
        {
            ans = min(m + m, ans);
            r = m - 1ll;
        }
        else
            l = m + 1ll;
    }


    used[last] = 0;
    bool fnd = (ans % 1);
    if (n > mod)
    {
        vector<LL> v;
        int k = N;
        while (k--)
            v.push_back((LL)rand() * (LL)rand());
        for (LL I = 0; I < v.size() && ans % 2 == 0; I++)
        {
            LL i = v[I];
            if (!used[i] && !used[i + ans - 1ll])
            {
                used[last] = 1;
                LL a = i, b = i + ans - 1ll;
                if (b == last)
                    swap(a, b);
                if (a != last)
                    get(a);
                get(b);
                fnd = 1;
                break;
            }
        }
    }
    for (LL i = 1; i + ans - 1ll <= n && ans % 2 == 0; i++)
        if (!used[i] && !used[i + ans - 1ll])
        {
            used[last] = 1;
            LL a = i, b = i + ans - 1ll;
            if (b == last)
                swap(a, b);
            if (a != last)
                get(a);
            get(b);
            fnd = 1;
            break;
        }
    cout << "= " << ans << endl;
}
//
int main()
{
    fastIO;
    int T;
    cin >> T;
    while (T--)
        solve();
    return 0;
}

/*


*/

Compilation message (stderr)

Colors.cpp: In function 'void solve()':
Colors.cpp:92:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (LL I = 0; I < v.size() && ans % 2 == 0; I++)
                        ~~^~~~~~~~~~
Colors.cpp:85:10: warning: variable 'fnd' set but not used [-Wunused-but-set-variable]
     bool fnd = (ans % 1);
          ^~~

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