Submission #1097978

#	Time	Username	Problem	Language	Result	Execution time	Memory
1097978		MateiKing80	Colors (BOI20_colors)	C++17	100 / 100	2 ms	600 KiB

Colors

#include <bits/stdc++.h>

using namespace std;

using ll = long long;
#define int ll

bool query(int i)
{
    cout << "? " << i << endl;
    cin >> i;
    return i;
}

signed main()
{
    int n;
    cin >> n;
    int i = 0, c = 0, l = 1, r = n, d = -1;
    while(l < r)
    {
        l = (l + r - 1) / 2;
        c += d * l;
        l ++;
        i = max(i, 1LL - c);
        d *= -1;
    }
    query(i);
    l = 1, r = n, d = -1;
    while(l < r)
    {
        int m = (l + r - 1) / 2;
        i += d * m;
        if(query(i))
            r = m;
        else
            l = m + 1;
        d *= -1;
    }
    cout << "= " << l << endl;
}

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