Submission #1299165

#	Time	Username	Problem	Language	Result	Execution time	Memory
1299165		flo	Colors (BOI20_colors)	C++20	100 / 100	2 ms	404 KiB

Colors

#include <bits/stdc++.h>
#define task "testing"
#define ll long long
#define multitest 0
using namespace std;

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

void guess(ll x) {
	cout << "= " << x << endl;
}

void flo(int ID) {
	ll n; cin >> n;
	
	int sign = 1;
	
	ll l = 1, r = n-1, cur = n, s = n;
	
	while (l <= r) {
		ll mid = (l+r)/2;
		
		cur = min(cur, s += sign*mid);
		
		sign *= -1, l = mid+1;
	}
	
	l = 1, r = n-1, sign = -1;
	
	ll ans = n;
	
	bool trash = ask(cur);
	
	while (l <= r) {
		ll mid = (l+r)/2;
		
		cur += sign*mid, sign *= -1;
		
		bool c = ask(cur);
		
		if (c == 1) {
			r = (ans = mid)-1;
		}
		else {
			l = mid+1;
		}
	}
	
	guess(ans);
}

int main() {
	// ios_base::sync_with_stdio(0);
	// cin.tie(0); cout.tie(0);

	if (fopen(task".inp", "r")) {
		freopen(task".inp", "r", stdin);
		freopen(task".out", "w", stdout);
	}

	int TCS = 1, ID = 1;

	if (multitest) {
		cin >> TCS;
	}

	while (TCS--) flo(ID++);

	return 0;
}

Compilation message (stderr)

Colors.cpp: In function 'int main()':
Colors.cpp:63:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   63 |                 freopen(task".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Colors.cpp:64:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |                 freopen(task".out", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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