Submission #940598

#	Time	Username	Problem	Language	Result	Execution time	Memory
940598		marvinthang	Secret Permutation (RMI19_permutation)	C++17	100 / 100	1303 ms	688 KiB

permutation

/*************************************
*    author: marvinthang             *
*    created: 19.03.2023 14:18:40    *
*************************************/
// https://oj.uz/problem/view/RMI19_permutation

#include "permutation.h"
#include <bits/stdc++.h>

using namespace std;

#define                  fi  first
#define                  se  second
#define                left  ___left
#define               right  ___right
#define                TIME  (1.0 * clock() / CLOCKS_PER_SEC)
#define             MASK(i)  (1LL << (i))
#define           BIT(x, i)  ((x) >> (i) & 1)
#define  __builtin_popcount  __builtin_popcountll
#define              ALL(v)  (v).begin(), (v).end()
#define           REP(i, n)  for (int i = 0, _n = (n); i < _n; ++i)
#define          REPD(i, n)  for (int i = (n); i--; )
#define        FOR(i, a, b)  for (int i = (a), _b = (b); i < _b; ++i) 
#define       FORD(i, b, a)  for (int i = (b), _a = (a); --i >= _a; ) 
#define       FORE(i, a, b)  for (int i = (a), _b = (b); i <= _b; ++i) 
#define      FORDE(i, b, a)  for (int i = (b), _a = (a); i >= _a; --i) 
#define        scan_op(...)  istream & operator >> (istream &in, __VA_ARGS__ &u)
#define       print_op(...)  ostream & operator << (ostream &out, const __VA_ARGS__ &u)
#ifdef LOCAL
		#include "debug.h"
#else
		#define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
		#define DB(...) 23
		#define db(...) 23
		#define debug(...) 23
#endif

template <class U, class V> scan_op(pair <U, V>)  { return in >> u.fi >> u.se; }
template <class T> scan_op(vector <T>)  { for (size_t i = 0; i < u.size(); ++i) in >> u[i]; return in; }
template <class U, class V> print_op(pair <U, V>)  { return out << '(' << u.first << ", " << u.second << ')'; }
template <size_t i, class T> ostream & print_tuple_utils(ostream &out, const T &tup) { if constexpr(i == tuple_size<T>::value) return out << ")";  else return print_tuple_utils<i + 1, T>(out << (i ? ", " : "(") << get<i>(tup), tup); }
template <class ...U> print_op(tuple<U...>) { return print_tuple_utils<0, tuple<U...>>(out, u); }
template <class Con, class = decltype(begin(declval<Con>()))> typename enable_if <!is_same<Con, string>::value, ostream&>::type operator << (ostream &out, const Con &con) { out << '{'; for (__typeof(con.begin()) it = con.begin(); it != con.end(); ++it) out << (it == con.begin() ? "" : ", ") << *it; return out << '}'; }

// end of template

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count()); 
template <class T> T rand(T l, T h) { return uniform_int_distribution <T> (l, h) (rng); } 
template <class T> T rand(T h) { return uniform_int_distribution <T> (0, h - 1) (rng); } 

vector <bool> used;
vector <long long> d;
vector <int> res;

bool backtracking(int i, int n) {
	if (i == n) return abs(res[0] - res[n - 1]) == d[0];
	if (!i) {
		REP(j, n) {
			res[i] = j;
			used[j] = true;
			if (backtracking(i + 1, n)) return true;
			used[j] = false;
		}
	} else {
		int x = res[i - 1] + d[i];
		if (x < n && !used[x]) {
			res[i] = x;
			used[x] = true;
			if (backtracking(i + 1, n)) return true;
			used[x] = false;
		}
		x = res[i - 1] - d[i];
		if (x >= 0 && !used[x]) {
			res[i] = x;
			used[x] = true;
			if (backtracking(i + 1, n)) return true;
			used[x] = false;
		}
	}
	return false;
}

void solve(int n) {
	vector <int> v(n);
	iota(ALL(v), 1);
	REP(_, 10) shuffle(ALL(v), rng);
	d.resize(n);
	long long total = 0;
	REP(i, n) {
		d[i] = query(v);
		total += d[i];
		rotate(v.begin(), v.begin() + 1, v.end());
	}
	total /= n - 1;
	REP(i, n) d[i] = total - d[i];
	used.assign(n, 0);
	res.resize(n);
	backtracking(0, n);
	vector <int> ans(n);
	REP(i, n) ans[v[i] - 1] = res[i] + 1;
	answer(ans);
}

#ifdef LOCAL

namespace A {
	int N;
	const int MAX_N = 1000;
	int P[1 + MAX_N];
	int queries = 0;
	
	void readInput() {
		//printf("The permutation you have to guess is:\n");
		scanf("%d", &N);
		for (int i = 1; i <= N; i++) {
			// P[i] = i;
			scanf("%d", &P[i]);
			//printf("%d ", P[i]);
		}
		// shuffle(P + 1, P + 1 + N, rng);
		//printf("\n");
	}
	
	int query(int V[]) {
		queries++;
		printf("query(");
		for (int i = 0; i < N - 1; i++) {
			printf("%d, ", V[i]);
		}
		printf("%d) = ", V[N - 1]);
		int freq[1 + N];
		for (int i = 0; i <= N; i++) {
			freq[i] = 0;
		}
		for (int i = 0; i < N; i++) {
			freq[V[i]]++;
		}
		for (int i = 1; i <= N; i++) {
			assert(freq[i] == 1);
		}
		int answer = 0;
		for (int i = 0; i + 1 < N; i++) {
			answer += abs(P[V[i + 1]] - P[V[i]]);
		}
		printf("%d\n", answer);
		fflush(stdout);
		return answer;
	}

	void answer(int V[]) {
		bool ok = true;
		for (int i = 1; i <= N; i++) {
			ok &= (V[i - 1] == P[i]);
		}
		if (ok) {
			printf("Correct! with N = %d, Q = %d\n", N, queries);
		} else {
			printf("Wrong answer!\n");
		}
		exit(0);
	}
}

int query(int p[]) {
	return A::query(p);
}

void answer(int ans[]) {
	A::answer(ans);
}

int query(std::vector<int> v) {
	int array[A::N];
	for (int i = 0; i < A::N; i++) {
		array[i] = v[i];
	}
	return query(array);
}

void answer(std::vector<int> v) {
	int array[A::N];
	for (int i = 0; i < A::N; i++) {
		array[i] = v[i];
	}
	answer(array);
}

int main() {
	file("PERMUTATION");
	A::readInput();
	solve(A::N);
	return 0;
}
#endif

Compilation message (stderr)

stub.cpp: In function 'int query(int*)':
stub.cpp:15:9: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |   fscanf(stdin, "%d", &x);
      |   ~~~~~~^~~~~~~~~~~~~~~~~
stub.cpp: In function 'int main(int, char**)':
stub.cpp:48:9: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   48 |   fscanf(stdin, "%d", &N);
      |   ~~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 35 / 35
• Subtask 3: 50 / 50