Submission #254678

#	Time	Username	Problem	Language	Result	Execution time	Memory
254678		Sorting	Parrots (IOI11_parrots)	C++14	98 / 100	11 ms	1792 KiB

encoder

#include "encoder.h"
#include "encoderlib.h"
#include <bits/stdc++.h>

using namespace std;

void encode(int N, int M[]){
    if(N >= 16){
        mt19937 mt(8);
        auto rnd = [&](int mod){
            return mt() % mod;
        };

        int p[64];
        for(int i = 0; i < N; ++i)
            p[i] = i;
        random_shuffle(p, p + N, rnd); 

        int prev = 0;
        for(int i = 0; i < N; ++i){
            for(int j = 0; j <= 7; ++j){
                if((M[p[i]] ^ prev) & (1 << j)){
                    if(i >= 32){
                        send((i - 32) * 8 + j);
                        send((i - 32) * 8 + j);
                    }
                    else send(i * 8 + j);
                }
            }
            prev = M[p[i]];
        }
        return;
    }

    for(int i = 0; i < N; ++i){
        for(int j = 0; j <= 7; ++j){
            if(M[i] & (1 << j))
                send(i * 8 + j);
        }
    }
}

decoder

#include "decoder.h"
#include "decoderlib.h"
#include <bits/stdc++.h>

using namespace std;

static int e[256];

void decode(int N, int L, int X[]){
    for(int i = 0; i < 256; ++i)
        e[i] = 0;

    if(N >= 16){
        for(int i = 0; i < L; ++i)
            e[X[i]]++;

        mt19937 mt(8);
        auto rnd = [&](int mod){
            return mt() % mod;
        };

        int p[64];
        for(int i = 0; i < N; ++i)
            p[i] = i;
        random_shuffle(p, p + N, rnd);

        int ans[64];
        int prev = 0;
        for(int i = 0; i < N; ++i){
            int curr = 0;
            for(int j = 0; j <= 7; ++j){
                if(i >= 32){
                    if(e[(i - 32) * 8 + j] & 2)
                        curr += (1 << j);
                }
                else{
                    if(e[i * 8 + j] & 1)
                        curr += (1 << j);
                }
            }
            prev ^= curr;
            ans[p[i]] = prev;
        }

        for(int i = 0; i < N; ++i)
            output(ans[i]);

        return;
    }

    for(int i = 0; i < L; ++i)
        e[X[i]] = true;

    for(int i = 0; i < N; ++i){
        int curr = 0;
        for(int j = 0; j <= 7; ++j){
            if(e[i * 8 + j])
                curr += (1 << j);
        }
        output(curr);
    }
}

• Subtask 1: 17 / 17
• Subtask 2: 17 / 17
• Subtask 3: 18 / 18
• Subtask 4: 29 / 29
• Subtask 5: 17 / 19