Submission #748191

#	Time	Username	Problem	Language	Result	Execution time	Memory
748191		Szil	Data Transfer (IOI19_transfer)	C++17	100 / 100	1450 ms	2496 KiB

transfer

    #include "transfer.h"
     
    #include <bits/stdc++.h>
     
    using namespace std;
     
    vector<int> get_attachment(vector<int> source) {
    	vector<int> res;
    	int K = (source.size()<100?6:8);
    	int safe = 0;
    	for (int i = 0; i < K; i++) {
    		int x = 0;
    		int block = 1 << i;
    		for (int j = 0; j < source.size(); j++) {
    			if ((j / block) % 2 == 0) {
    				x ^= source[j];
    			}
    		}
    		res.push_back(x);
    		safe ^= x;
    	}
    	res.push_back(safe);
    	return res;
    }
     
    vector<int> retrieve(vector<int> data) {
    	int n;
    	if (data.size() < 100) {
    		n = 63;
    	} else {
    		n = 255;
    	}
    	int safe = data.back();
    	vector<int> source = vector<int>(data.begin(), data.begin()+n);
    	vector<int> cnt(n);
    	vector<int> v = vector<int>(data.begin()+n, data.end()-1);
    	int K = (source.size()<100?6:8);
    	int p = 0;
    	for (int i : v) p ^= i;
    	if (p != safe) return source;
    	for (int i = 0; i < K; i++) {
    		int x = 0;
    		int block = 1 << i;
    		for (int j = 0; j < n; j++) {
    			if ((j / block) % 2 == 0) {
    				x ^= source[j];
    			}
    		}
    		for (int j = 0; j < n; j++) {
    			if ((j / block) % 2 == (x == v[i])) {
    				cnt[j]++;
    			}
    		}
    	}
    	for (int i = 0; i < n; i++) {
    		if (cnt[i] == K) {
    			source[i] ^= 1;
    			return source;
    		}
    	}
    	return source;
    }

Compilation message (stderr)

transfer.cpp: In function 'std::vector<int> get_attachment(std::vector<int>)':
transfer.cpp:14:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   14 |       for (int j = 0; j < source.size(); j++) {
      |                       ~~^~~~~~~~~~~~~~~

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