Submission #213573

#	Time	Username	Problem	Language	Result	Execution time	Memory
213573		_Ice_Tea_	Data Transfer (IOI19_transfer)	C++14	100 / 100	337 ms	2924 KiB

transfer

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

#define de(x) if( x && x == MODE)
#define MODE 0

using namespace std;

std::vector<int> get_attachment(std::vector<int> source) {

	int i,j,k;

	int N = source.size();
	int L = ( N == 63 ? 6 : 8 );
	// int L = 3;

	vector<int> attach;
	for( i=0; i<L; i++)
	{
		int key = 0;
		for( j=0; j<N; j++)
		{
			if( (j>>i)&1 )
				continue;
			key ^= source[j];
		}
		attach.push_back(key);
	}

	int key = 0;
	for( auto it:attach)
		key ^= it;
	attach.push_back(key);
	de(1)
	{
		printf(">>> ");
		for( auto it:attach)
			printf("%d ", it);
		printf("\n");
	}

	return attach;
}

std::vector<int> retrieve(std::vector<int> data) {

	int i,j;

	int N = ( data.size() == 70 ? 63 : 255);
	// int N = 7;
	int L = data.size() - N - 1;

	vector<int> ans;
	int arr[256];

	int idx = 0;
	for( i=0; i<L; i++)
	{
		int key = 0;
		for( j=0; j<N; j++)
		{
			if( (j>>i)&1 )
				continue;
			key ^= data[j];
		}

		if( key == data[ N+i ])
			idx ^= (1<<i);
	}

	de(1) printf("idx = %d\n", idx);

	for( i=0; i<N; i++)
		ans.push_back( data[i] );
	if( idx == N)
	{
		// return ans;
	}
	else
	{
		int key = 0;
		for( i=0; i<L; i++)
			key ^= data[ N+i ];

		if( key != data.back())
		{
			// return ans;
		}
		else
		{
			ans[idx] ^= 1;
			// return ans;
		}
	}

	de(1)
	{
		printf("ans = ");
		for( auto it: ans)
			printf("%d", it);
		printf("\n");
	}
	return ans;
}

Compilation message (stderr)

transfer.cpp: In function 'std::vector<int> get_attachment(std::vector<int>)':
transfer.cpp:11:10: warning: unused variable 'k' [-Wunused-variable]
  int i,j,k;
          ^
transfer.cpp: In function 'std::vector<int> retrieve(std::vector<int>)':
transfer.cpp:54:6: warning: unused variable 'arr' [-Wunused-variable]
  int arr[256];
      ^~~

• Subtask 1: 60 / 60
• Subtask 2: 40 / 40