Submission #581640

#	Time	Username	Problem	Language	Result	Execution time	Memory
581640		penguinhacker	Zagrade (COI20_zagrade)	C++17	100 / 100	912 ms	800 KiB

zagrade

#include <bits/stdc++.h>
using namespace std;
 
#define ll long long
#define ar array
 
const int mxN=1e5;
int n, q, match[mxN];
 
bool qry(int l, int r) {
	cout << "? " << l+1 << " " << r+1 << endl;
	bool res;
	cin >> res;
	return res;
}
 
int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> n >> q;
	memset(match, -1, sizeof(match));
	string ans(n, '0');
	for (int i=1; i<n;) { // right bound of current bracket sequence
		if (qry(i-1, i)) { // found
			match[i-1]=i, match[i]=i-1;
			ans[i-1]='(', ans[i]=')';
			int j=i-1;
			if (j&&match[j-1]!=-1) {
				j=match[j-1];
				match[i]=j, match[j]=i;
			}
			while(j&&i+1<n&&qry(j-1, i+1)) {
				++i, --j;
				match[i]=j, match[j]=i;
				ans[j]='(', ans[i]=')';
				if (j&&match[j-1]!=-1) {
					j=match[j-1];
					match[i]=j, match[j]=i;
				}
			}
			i+=2;
		} else
			++i;
	}
	int cnt=count(ans.begin(), ans.end(), '(');
	for (int i=0; i<n; ++i)
		if (ans[i]=='0') {
			if (cnt<n/2)
				ans[i]=')', ++cnt;
			else
				ans[i]='(';
		}
	cout << "! " << ans << endl;
	return 0;
}

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