Submission #232488

#	Time	Username	Problem	Language	Result	Execution time	Memory
232488		tjd229	Secret Permutation (RMI19_permutation)	C++14	0 / 100	5 ms	256 KiB

permutation

#include  "permutation.h"
#include <vector>
using namespace std;


int Tx[257], x[257];
int use[257];
int _N;

bool recon(int ix,vector<int> &P) {

	int bk = P.back();
	//
	if (ix == _N) {
		int d = bk - P[0];
		if (d < 0) d = -d;
		return d == x[1];
	}
	int nxt = bk + x[ix+1];
	if (nxt <= _N && use[nxt] == 0) {
		use[nxt] = 1;
		P.push_back(nxt);
		if (recon(ix + 1, P)) return 1;
		P.pop_back();
		use[nxt] = 0;
	}
	nxt = bk - x[ix+1];
	if (nxt > 0 && use[nxt] == 0) {
		use[nxt] = 1;
		P.push_back(nxt);
		if (recon(ix + 1, P)) return 1;
		P.pop_back();
		use[nxt] = 0;
	}
	return 0;
}
void solve(int N) {
	_N = N;
	int sum = 0;
	vector<int> P;
	for (int i = 1; i <= N; ++i) {
		vector<int> V;
		for (int j = 0; j < N; ++j) {
			int x = i + j;
			if (x > N) x -= N;
			V.push_back(x);
		}
		Tx[i]=query(V);
		sum += Tx[i];
		use[i] = 0;
	}
	int T = sum / (N - 1);
	
	for (int i = 1; i <= N; ++i) x[i] = T-Tx[i] ;
	
	for (int i = 1; i <= N; ++i) {
		P.push_back(i); use[i] = 1;
		if (recon(1, P)) {
			answer(P);
			break;
		}
		P.pop_back(); use[i] = 0;
	}
}

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]
   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]
   fscanf(stdin, "%d", &N);
   ~~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 15
• Subtask 2: 0 / 35
• Subtask 3: 0 / 50