Submission #1003856

#	Time	Username	Problem	Language	Result	Execution time	Memory
1003856		vjudge1	Zagrade (COI20_zagrade)	C++17	100 / 100	665 ms	5876 KiB

zagrade

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define pb push_back
#define mp make_pair
#define fr first
#define sc second
#define all(x) x.begin(),x.end()
const int maxn = 5e5+10;
const int inf = 1e18+10;
int n;
int query(int l, int r) {
	if(l > r) return 0;
	if(l < 0 or r >= n) return 0;
	cout << "? " << l+1 << " " << r+1 << endl;
	cout.flush(); 
	int x; cin >> x;
	return x;
}

int32_t main() {
	// #ifndef ONLINE_JUDGE
	// freopen("in.in","r",stdin);
	// freopen("out.out","w",stdout);
	// #endif

	int q;
	cin >> n >> q;
	vector<int> ans(n,0);
	int antok = -inf;
	int pos = 0;
	int qtd = n/2;

	set<int> ids;
	for(int i = 0; i < n; i++) ids.insert(i);

	for(int r = 1; r < n; r++) {
		auto it = ids.find(r);
		if(it == ids.begin()) continue;
		it = prev(it);
		int l = *it;

		if(query(l,r)) {
			ans[l] = +1;
			ans[r] = -1;
			ids.erase(l);
			ids.erase(r);
			qtd--;
		}
	}

	// while(pos+1 < n) {
	// 	int l = pos+1;
	// 	int r = pos;
	// 	while(l-1 > antok && query(l-1,r+1)) {
	// 		l--;
	// 		r++;
	// 		ans[l] = +1;
	// 		ans[r] = -1;
	// 		qtd--;
	// 	}
	// 	if(l <= r) antok = r;
	// 	pos = r+1;
	// }

	for(int i = 0; i < n; i++) {
		if(ans[i] == 0) {
			if(qtd == 0) {
				ans[i] = +1;
			}
			else {
				qtd--;
				ans[i] = -1;
			}
		}
	}

	cout << "! ";
	for(int i = 0; i < n; i++) {
		if(ans[i] == -1) cout << ')';
		else cout << '(';
	}
	cout.flush();
}

Compilation message (stderr)

zagrade.cpp: In function 'int32_t main()':
zagrade.cpp:30:6: warning: unused variable 'antok' [-Wunused-variable]
   30 |  int antok = -inf;
      |      ^~~~~
zagrade.cpp:31:6: warning: unused variable 'pos' [-Wunused-variable]
   31 |  int pos = 0;
      |      ^~~

• Subtask 1: 14 / 14
• Subtask 2: 7 / 7
• Subtask 3: 57 / 57
• Subtask 4: 22 / 22