Submission #417054

#	Time	Username	Problem	Language	Result	Execution time	Memory
417054		aryan12	Colors (BOI20_colors)	C++17	22 / 100	5 ms	280 KiB

Colors

#include <bits/stdc++.h>
using namespace std;
#define int long long

void BinSrch(int l, int r, int cnt, int ans, int subtask, int n) {
    int f = 0;
    while(l <= r) {
        int response;
        if(cnt % 2 == 0) {
            if(subtask == 2 && l == n / 2)
                break;
            cout << "? " << l++ << endl;
        }
        else {
            if(subtask == 2 && r == n / 2)
                break;
            cout << "? " << r-- << endl;
        }
        cnt++;
        cin >> response;
        if(cnt == 1)
            continue;
        if(response == 1) {
            ans = min(ans, r - l + 2);
        }
        else {
            cout << "= " << ans << endl;
            f = 1;
            break;
        }
    }
    if(f == 0) {
        cout << "= " << ans << endl;
    }
    //cout << "cnt of queries = " << cnt << endl;
}

void Solve() {
    int n;
    cin >> n;
    if(n <= 64) {
        BinSrch(1, n, 0, n, 1, n);
        return;
    }
    int l = 1, r = n, ans = n;
    cout << "? " << n / 2 << endl;
    int response;
    cin >> response;
    cout << "? " << n << endl;
    cin >> response;
    if(response == 1) {
        l = n / 2 + 1, r = n - 1, ans = n - n / 2;
    }
    else {
        l = 1, r = n - 1;
    }
    BinSrch(l, r, 2, ans, 2, n);
}

int32_t main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    Solve();
    return 0;
}

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