Submission #401219

#	Time	Username	Problem	Language	Result	Execution time	Memory
401219		rocks03	Data Transfer (IOI19_transfer)	C++14	100 / 100	82 ms	2544 KiB

transfer

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define ff first
#define ss second
#define pb push_back
#define SZ(x) ((int)(x).size())
#define all(x) x.begin(), x.end()
#define debug(x) cout << #x << ": " << x << " "
#define nl cout << "\n"
#define rep(i, a, b) for(int i = (a); i < (b); i++)
#define per(i, a, b) for(int i = (a); i >= (b); i--)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

vector<int> get_attachment(vector<int> source) {
    int N = SZ(source), K;
    if(N == 63) K = 6;
    else if(N == 255) K = 8;
    int x = 0, s = 0;
    rep(i, 0, N){
        if(source[i] == 1) x ^= (i + 1), s++;
    }
    vector<int> ans;
    rep(i, 0, K) ans.pb((x >> i) & 1);
    ans.pb(s % 2);
    return ans;
}

vector<int> retrieve(vector<int> data){
    int N = SZ(data), K;
    if(N >= 255) N = 255, K = 8;
    else N = 63, K = 6;
    int x = 0, s = 0;
    rep(i, 0, N){
        if(data[i] == 1) x ^= (i + 1), s++;
    }
    int x2 = 0;
    rep(i, 0, K) if(data[N + i] == 1) x2 ^= (1 << i);
    vector<int> ans;
    if(x == x2 || s % 2 == data.back()) ans = vector<int>(data.begin(), data.begin() + N);
    else{
        data[(x ^ x2) - 1] ^= 1;
        ans = vector<int>(data.begin(), data.begin() + N);
    }
    return ans;
}

Compilation message (stderr)

transfer.cpp: In function 'std::vector<int> get_attachment(std::vector<int>)':
transfer.cpp:13:41: warning: 'K' may be used uninitialized in this function [-Wmaybe-uninitialized]
   13 | #define rep(i, a, b) for(int i = (a); i < (b); i++)
      |                                         ^
transfer.cpp:18:25: note: 'K' was declared here
   18 |     int N = SZ(source), K;
      |                         ^

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