Submission #71516

#	Time	Username	Problem	Language	Result	Execution time	Memory
71516		FLDutchman	Parrots (IOI11_parrots)	C++14	99 / 100	62 ms	2584 KiB

encoder

#include "encoder.h"
#include "encoderlib.h"
#include <bits/stdc++.h>
using namespace std;

typedef int INT;

#define FOR(i,l,r) for(int i = (l); i < (r); i++)
#define snd second
#define fst first
#define V vector
#define pb push_back

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int, int> ii;
typedef vector<ii> vii;


void encode(int N, int M[]){
	if(N < 16) FOR(i, 0, N) FOR(j, 0, 8) {if(M[i]&(1<<j)) send( (i<<3)+j);} 
	else {
		vi bestcode; 
		int bestcnt = 1e9;
		FOR(seed, 0, 256){
			srand(seed);
			int cnt = 0;
			vi code(256, 0);

			FOR(i, 0, N) {
				int r = (rand() % 256);
				FOR(j, 0, 4){
					int m = M[i] ^ r;
					int k = (m>>(2*j))& 3 ;
					//cerr << cnt << endl;
					code[( (i<<2)+j)] += k;
					cnt += k;
				}
			}
			code[seed] += 4;
			cnt += 4;
			if(cnt < bestcnt) {
				bestcnt = cnt;
				bestcode = code;
			}
		}
		//cout<<bestcnt<<endl;
		//for(int k : bestcode) cout << k << " ";
		//cout<<endl;
		FOR(i, 0, 256)FOR(j, 0, bestcode[i]) send(i);

	}
}

decoder

#include "decoder.h"
#include "decoderlib.h"
#include <bits/stdc++.h>
using namespace std;

typedef int INT;

#define FOR(i,l,r) for(int i = (l); i < (r); i++)
#define snd second
#define fst first
#define V vector
#define pb push_back

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int, int> ii;
typedef vector<ii> vii;


void decode(int N, int L, int X[]) {
	if(N < 16){
		vi msg(N, 0) ;
		FOR(i, 0, L) msg[ (X[i]) >>3] |= 1<<(X[i]&7);
		FOR(i, 0, N) output(msg[i]);
	} else {
		//cerr << "{ ";
		//FOR(i, 0, 64) cerr << rand() % 256 << ", ";
		//cerr << "}"<<endl;
		vi msg(256, 0);
		FOR(i, 0, L) msg[X[i]]++;
		int seed = 0;
		for(; msg[seed] < 4; seed++);
		srand(seed);

		FOR(i, 0, N) {
			int c = 0;
			FOR(k, 0, 4) c |= (msg[4*i+k] & 3) << (2*k);
			c ^= (rand() % 256);
			//cerr<<c<<endl;
			output(c);
		}


	}
}

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