Submission #571851

#	Time	Username	Problem	Language	Result	Execution time	Memory
571851		RandomLB	Data Transfer (IOI19_transfer)	C++17	100 / 100	98 ms	2504 KiB

transfer

#include <bits/stdc++.h>
using namespace std;
 
std::vector<int> get_attachment(std::vector<int> source) {
	std::vector<int> v;
	int x = 0;
	for (int i = 0; i < source.size(); i++)
		if (source[i]) x ^= (i + 1);

	int last = 0;
	if (source.size() < 64) {
		for (int i = 0; i < 6; i++) {
			v.push_back(x & 1);
			if (x & 1) last = 1 - last;
			x >>= 1;
		}
	} else {
		for (int i = 0; i < 8; i++) {
			v.push_back(x & 1);
			if (x & 1) last = 1 - last;
			x >>= 1;
		}
	}
	v.push_back(last);
	return v;
}
 
std::vector<int> retrieve(std::vector<int> v){
    int n = ((int)v.size() < 100? 63 : 255);
    int xr = 0;
    std::vector<int> res;
    for (int i = 0; i < n; i++){
        xr ^= (i+1)*v[i];
        res.push_back(v[i]);
    }
    int check = 0, on = 0;
    for (int i = 0; i < (n==63?6:8); i++){
        if (v[n+i]){
            check ^= (1<<i);
            on ^= 1;
        }
    }
    if (xr != check && on == v.back()) res[(xr^check)-1] ^= 1;
    return res;
}

Compilation message (stderr)

transfer.cpp: In function 'std::vector<int> get_attachment(std::vector<int>)':
transfer.cpp:7:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    7 |  for (int i = 0; i < source.size(); i++)
      |                  ~~^~~~~~~~~~~~~~~

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