Submission #414840

#	Time	Username	Problem	Language	Result	Execution time	Memory
414840		amoo_safar	City (JOI17_city)	C++17	100 / 100	520 ms	43072 KiB

Encoder

#include "Encoder.h"
#include <bits/stdc++.h>

using namespace std;


const int N = 33e4;
const int bl = 100;
const int sd = 58;

int mk[N];
mt19937 rng(sd);
vector<int> V;

vector<int> G[N];
int st[N], fn[N], T = 0;

void DFS(int u, int p){
	st[u] = T ++;
	shuffle(G[u].begin(), G[u].end(), rng);
	bool fl = false;
	for(auto adj : G[u])
		if((adj != p) && ((int) G[adj].size() == 1))
			fl = true;
	if(fl){
		for(auto adj : G[u]){
			if(adj != p && G[adj].size() == 1){
				st[adj] = T;
				fn[adj] = T + 1;
			}
		}
		T ++;
	} 
	for(auto adj : G[u])
		if(adj != p && G[adj].size() > 1)
			DFS(adj, u);
	fn[u] = T;

	while(mk[fn[u] - st[u] ] == -1){
		fn[u] ++;
		T ++;
	}
	// cerr << "!! " << u << ' ' << st[u] << ' ' << fn[u] << '\n'; 
}

void Encode(int _n, int A[], int B[]){
	memset(mk, -1, sizeof mk);
	int cnt = 0;

	for(int i = 1; i < N; i++){
		int pr = (i + bl - 1) / bl;
		// if(i > N / 2) pr += pr;
		uniform_int_distribution<> Amoo(1, pr);
		if(Amoo(rng) == 1){
			mk[i] = V.size();
			V.push_back(i);
		}
	}
	int sz = V.size();
	for(int i = 0; i < _n - 1; i++)
		G[A[i]].push_back(B[i]), G[B[i]].push_back(A[i]);
	T = 0;
	DFS(0, -1);
	cerr << "! " << V.size() << '\n';
	// for(int i = 0; i < _n; i++)
	// 	cerr << "! " << st[i] << ' ' << fn[i] << '\n';
	
	for(int i = 0; i < _n; i++){
		Code(i, 1ll * sz * st[i] + mk[fn[i] - st[i]]);
	}
}

Device

#include "Device.h"

#include <bits/stdc++.h>

using namespace std;

const int N = 33e4;
const int bl = 100;
const int sd = 58;

mt19937 rng2(sd);
vector<int> V2;

void InitDevice(){
	for(int i = 1; i < N; i++){
		int pr = (i + bl - 1) / bl;
		uniform_int_distribution<> Amoo(1, pr);

		if(Amoo(rng2) == 1)
			V2.push_back(i);
	}
}

int Answer(long long S, long long T){
	if(S == T)
		return 2;
	int sz = V2.size();
	int s1 = S / sz, f1 = s1 + V2[S % sz];
	int s2 = T / sz, f2 = s2 + V2[T % sz];

	if(s2 <= s1 && s1 < f2) return 0;
	if(s1 <= s2 && s2 < f1) return 1;
	return 2;
}

Compilation message (stderr)

Encoder.cpp: In function 'void Encode(int, int*, int*)':
Encoder.cpp:48:6: warning: unused variable 'cnt' [-Wunused-variable]
   48 |  int cnt = 0;
      |      ^~~

• Subtask 1: 8 / 8
• Subtask 2: 92 / 92