제출 #931392

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
931392		qwusha	Colors (BOI20_colors)	C++17	100 / 100	1 ms	708 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;
        ll var1 = last + sz, var2 = last - sz;
        if (st.find(var1) != st.end() || var1 > n)
            ind = var2;
        else if (st.find(var2) != st.end() || var2 <= 0)
            ind = var1;
        else if (var2 > (n + 1 - var1))
            ind = var2;
        else
            ind = var1;
        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: 13 / 13
• Subtask 3: 21 / 21
• Subtask 4: 24 / 24
• Subtask 5: 33 / 33