Submission #394237

#	Time	Username	Problem	Language	Result	Execution time	Memory
394237		jsannemo	Password (RMI18_password)	C++14	80 / 100	629 ms	864 KiB

password

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

#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;

int query(string q);

vector<int> seen(26);
string alpha;

string go(const string& pre, int N, int S) {
	if (S < 0) return "";
	swap(alpha[S], alpha[rand() % (S + 1)]);


	string q = pre + string(N - sz(pre), alpha[S]);
	int cnt = query(q) - seen[alpha[S] - 'a'] - sz(pre);
	//cerr << "pre " << pre << " S " << alpha[S] << " cnt " << cnt << endl;

	string npre = pre + string(cnt, alpha[S]);
	vector<string> tres;
	for (int i = cnt; i >= 0; --i) {
		tres.push_back(go(npre, N, S - 1));
		npre.pop_back();
	}
	seen[alpha[S] - 'a'] += cnt;

	string res;
	for (int i = sz(tres) - 1; i >= 0; --i) {
		res.insert(res.end(), all(tres[i]));
		if (i) res.push_back(alpha[S]);
	}
	return res;
}

string guess(int N, int S) {
	srand(time(NULL));
	rep(i,0,S) alpha.push_back('a' + i);
	return go("", N, S - 1);
}

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 30 / 30
• Subtask 5: 0 / 20