Submission #1030349

#	Time	Username	Problem	Language	Result	Execution time	Memory
1030349		thinknoexit	Colors (BOI20_colors)	C++17	0 / 100	0 ms	344 KiB

Colors

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
ll now = 0;
bool ask(ll x) {
    now = x;
    cout << "? " << x << endl;
    cin >> x; return x;
}
void answer(ll x) {
    cout << "= " << x << endl;
    exit(0);
}
int main() {
    cin.tie(nullptr)->sync_with_stdio(false);
    ll n;
    cin >> n;
    ll l = 1, r = n;
    ask(1);
    while (l < r) {
        if (now == l) {
            if (ask(r)) l += 2;
            else answer(r - l + 1);
        }
        else {
            if (ask(l)) r -= 2;
            else answer(r - l + 1);
        }
    }
    if (now == l) {
        r += 2;
        // r - l == 1
        if (r - l == 1) {
            answer(1);
        }
        else if (r - l == 2) {
            if (ask(r - 1)) answer(1);
            else answer(2);
        }
    }
    else {
        l -= 2;
        if (r - l == 1) {
            answer(1);
        }
        else if (r - l == 2) {
            if (ask(l + 1)) answer(1);
            else answer(2);
        }
    }
    return 0;
}

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