제출 #680506

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
680506		jhwest2	Colors (BOI20_colors)	C++17	0 / 100	0 ms	208 KiB

Colors

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

typedef long long ll;
ll n;

bool debug = 1;

int last = 0, C = 1;
bool ask(ll x) {
    assert(1 <= x && x <= n);
    bool res; 
    cout << "? " << x << endl;
    if (debug) {
        if (abs(last - x) >= C)
            res = 1;
        else
            res = 0;
        
        last = x;
        cout << res << endl;
    }
    else
        cin >> res;

    return res;
}
int main() {
    cin >> n;

    // finding the starting position
    ll L = 1, R = n, x = 0, dir = 0;
    ll minv = 0, maxv = 0;
    while (L < R) {
        ll M = (L + R) / 2;

        if (dir == 0) {
            x += M;
            maxv = max(maxv, x);
        }
        else {
            x -= M;
            minv = min(minv, x);
        }
        dir = 1 - dir;

        L = M + 1;
    }
    assert(maxv - minv <= n - 1);

    L = 1; R = n; x = 1 - minv; dir = 0;
    ask(x);
    while (L < R) {
        ll M = (L + R) / 2;

        bool r;
        if (dir == 0) {
            r = ask(x + M);
            x += M;
        }
        else {
            r = ask(x - M);
            x -= M;
        }
        dir = 1 - dir;

        if (r)
            R = M;
        else
            L = M + 1;
    }
    cout << "= " << L << endl;
}

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