Submission #829691

#	Time	Username	Problem	Language	Result	Execution time	Memory
829691		bane	Data Transfer (IOI19_transfer)	C++17	100 / 100	106 ms	2496 KiB

transfer

#include "transfer.h"
#include<vector>

using namespace std;

std::vector<int> get_attachment(std::vector<int> source) {
	int tot = 0;
	if (source.size() <= 63)tot = 6;
	else tot = 8;

	vector<int>adding(tot + 1, 0);
	int odd = 0;
	for (int i = 0; i < source.size(); i++){
		odd += source[i];
	}
	adding.back() = odd & 1;
	int a = 0;
	for (int i = 0; i < source.size(); i++){
		if (source[i]){
			a ^= (i + 1);
		}
	}
	for (int j = 0; j < tot; j++){
		if (a & (1 << j))adding[j] = 1;
	}
	return adding;
}

std::vector<int> retrieve(std::vector<int> data) {
	if (data.size() > 100){
		int odd = 0;
		for (int i = 0 ; i < 255; i++){
			odd += data[i];
		}
		odd = odd & 1;
		int xr = 0, xr2 = 0;
		for (int i = 0; i < 8; i++){
			if (data[255 + i])xr2 ^= (1 << i);
		}

		for (int i = 0; i < 255; i++){
			if (data[i])xr ^= (i + 1);
		}
	
		int ok = (xr == xr2);

		if (!ok){
			if (odd != data.back()){
				//first half is fucked
				for (int i = 0; i < 255; i++){
					if ((xr ^ (i + 1)) == xr2){
						data[i] ^= 1;
						//return data;
					}
				}
			}else{
				//second half is fucked
				for (int i = 0; i < 8; i++){
					if (((1 << i) ^xr2) == xr){
						data[255 + i] ^= 1;
						//return data;
					}
				}
			}
		}else{
			data.back() ^= 1;
		}
		vector<int>ans;
		for (int i = 0; i < 255; i++)ans.push_back(data[i]);
		return ans;
	}else{
		int odd = 0;
		for (int i = 0 ; i < 63; i++){
			odd += data[i];
		}
		odd = odd & 1;
		int xr = 0, xr2 = 0;
		for (int i = 0; i < 6; i++){
			if (data[63 + i])xr2 ^= (1 << i);
		}

		for (int i = 0; i < 63; i++){
			if (data[i])xr ^= (i + 1);
		}
	
		int ok = (xr == xr2);

		if (!ok){
			if (odd != data.back()){
				//first half is fucked
				for (int i = 0; i < 63; i++){
					if ((xr ^ (i + 1)) == xr2){
						data[i] ^= 1;
						//return data;
					}
				}
			}else{
				//second half is fucked
				for (int i = 0; i < 6; i++){
					if (((1 << i) ^xr2) == xr){
						data[63 + i] ^= 1;
						//return data;
					}
				}
			}
		}else{
			data.back() ^= 1;
			//return data;
		}
		vector<int>ans;
		for (int i = 0; i < 63; i++)ans.push_back(data[i]);
		return ans;
	}
	return data;
}

Compilation message (stderr)

transfer.cpp: In function 'std::vector<int> get_attachment(std::vector<int>)':
transfer.cpp:13:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   13 |  for (int i = 0; i < source.size(); i++){
      |                  ~~^~~~~~~~~~~~~~~
transfer.cpp:18:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   18 |  for (int i = 0; i < source.size(); i++){
      |                  ~~^~~~~~~~~~~~~~~

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