Submission #259872

#	Time	Username	Problem	Language	Result	Execution time	Memory
259872		_7_7_	Colors (BOI20_colors)	C++14	100 / 100	2 ms	416 KiB

Colors

#include <bits/stdc++.h>                                           
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
 
using namespace std;
using namespace __gnu_pbds;
 
#define int long long
//#pragma GCC optimize("Ofast")
//#pragma comment(linker, "/stack:200000000")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4")
 
 
#define file(s) freopen(s".in","r",stdin); freopen(s".out","w",stdout);
#define fastio ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
#define all(x) x.begin(), x.end()
#define sz(s) (int)s.size()
#define pb push_back
#define ppb pop_back
#define mp make_pair
#define s second
#define f first
 
 
 
 
typedef pair < long long, long long > pll;    
typedef pair < int, int > pii;  
typedef unsigned long long ull;         
typedef vector < pii > vpii;                                   	
typedef vector < int > vi;
typedef long double ldb;  
typedef long long ll;  
typedef double db;
 
typedef tree < int, null_type, less < int >, rb_tree_tag, tree_order_statistics_node_update > ordered_set;
 
const int inf = 1e9, maxn = 2e5 + 48, mod = 998244353, N = 1e5 + 512;
const int dx[] = {1, -1, 0, 0}, dy[] = {0, 0, 1, -1}, block = 300;
const pii base = mp(1171, 3307), Mod = mp(1e9 + 7, 1e9 + 9);
const db eps = 1e-12, pi = acos(-1);
const ll INF = 1e18;
 
int t, n;
int ask (int x) {
	cout << "? "<< x << endl;
	int y;
	cin >> y;
	return y;
}
 
 
main () {
//	cin >> t;
	t = 1;
	while (t--) {
		cin >> n;
		int X = n, pos = 0, f = 0;
		int l = 1, r = n - 1;
		while (l <= r) {
			int mid = (l + r) / 2;
			pos += (f ? 1 : -1) * mid;
			X = min(X, n - pos);
			f ^= 1;
			l = mid + 1;
		}
 
 
		ask(X);
		pos = 1;
		f = 0;
		l = 1, r = n - 1;
		int  res = n;
 
		while (l <= r) {
			int mid = (l + r) / 2;
			X += (f ? 1 : -1) * mid;
			if (ask(X)) {
				res = mid;
				r = mid - 1;
			} else
				l = mid + 1;
			f ^= 1;
		}
 
		cout << "= " << res << endl;
	}
}

Compilation message (stderr)

Colors.cpp:53:7: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main () {
       ^

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