Submission #931389

#	Time	Username	Problem	Language	Result	Execution time	Memory
931389		qwusha	Colors (BOI20_colors)	C++17	9 / 100	1 ms	600 KiB

Colors

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define fi first
#define se second
typedef long double ld;
const ll inf = 1e9;
const ld eps = 1e-8;
const ll logs = 32;
#include <cmath>

ll c(ll k) {
    cout << "? " << k << endl;
    ll x;
    cin >> x;
    return x;
}


signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    ll n;
    cin >> n;
    ll lsz = 0, rsz = n;
    ll va = n / 2, lva;
    ll dif = n / 2;
    ll left = 0, right = 0;
    ll t = 1;
    while (dif > 1) {
        lva = va;
        va = (va + n) / 2;
        dif = va -lva;
        if (t)
            left += dif;
        else
            right += dif;
        t = 1 - t;
    }
    ll last;
    if (!t)
        last = left + 1;
    else 
        last = n - (n / 2) - right;
    ll x = c(last);
    set<ll> st = {last};
    while (rsz - lsz > 1) {
        ll sz = (rsz + lsz) / 2;
        ll ind;
        if (last + sz <= n && st.find(last + sz) == st.end())
            ind = last + sz;
        else
            ind = last - sz;
        x = c(ind);
        st.insert(ind);
        if (x == 1) {
            rsz = sz;
        } else
            lsz = sz;
        last = ind;
    }
    cout << "= " << rsz << endl;
}

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