Submission #743834

#	Time	Username	Problem	Language	Result	Execution time	Memory
743834		boyliguanhan	Saveit (IOI10_saveit)	C++17	100 / 100	282 ms	10796 KiB

encoder

#include <bits/stdc++.h>
using namespace std;
#define PB push_back
#include "grader.h"
#include "encoder.h"
#define N 1010
static int p[N], d[N];
bool vis[N];
static vector<int> adj[N];
void dfs(int n) {
	vis[n] = 1;
	for(auto i : adj[n])
    if(!vis[i])
	    dfs(i), p[i] = n;
}
void encode(int n, int h, int m, int *A, int *B) {
	for(int i = 0; i < m; ++i) {
		adj[A[i]].PB(B[i]);
		adj[B[i]].PB(A[i]);
	}
	dfs(0);
	for(int i = 1; i < n; ++i)
		for(int j = 0; j < 10; ++j)
			encode_bit(bool(p[i] & (1<<j)));
	vector<int> x;
	for(int i = 0; i < h; ++i) {
		queue<int> q;
		memset(d, -1, sizeof d);
		q.push(i);
		d[i] = 0;
		while(!empty(q)) {
			int u = q.front(); q.pop();
			for(auto v : adj[u]) if(d[v] < 0)
				d[v] = d[u] + 1, q.push(v);
		}
		for(int u = 1; u < n; ++u)
			x.PB(1 + d[u] - d[p[u]]);
	}
	while(size(x) % 3) x.PB(0);
	for(int i = 0; i < size(x); i += 3) {
		int num = x[i] + x[i + 1] * 3 + x[i + 2] * 9;
		for(int j = 0; j < 5; ++j)
			encode_bit(bool(num & (1<<j)));
	}
	return;
}

decoder

#include <bits/stdc++.h>
using namespace std;
#include "grader.h"
#include "decoder.h"
#define N 1000
#define PB push_back
static int p[N], dif[N], H;
static vector<int> adj[N], x;
void dfs(int n, int par, int d) {
	hops(H, n, d);
	for(auto v : adj[n]) if(v != par)
		dfs(v, n, d + (n == p[v] ? dif[v] : -dif[n]));
}
void decode(int n, int h) {
	for(int i = 1; i < n; ++i) {
		for(int j = 0; j < 10; ++j)
			if(decode_bit()) p[i] |= 1<<j;
		adj[i].PB(p[i]);
		adj[p[i]].PB(i);
	}
	x.resize(n * h - h);
	while(size(x) % 3) x.PB(0);
	for(int i = 0; i < size(x); i += 3) {
		int num=0;
		for(int j = 0; j < 5; ++j)
			if(decode_bit()) num |= 1<<j;
		for(int j = 0; j < 3; ++j, num /= 3)
			x[i + j] = (num % 3) - 1;
	}
	for(int pos = H = 0; H < h; ++H) {
		for(int u = 1; u < n; ++u)
			dif[u] = x[pos++];
		dfs(H, H, 0);
	}
}

Compilation message (stderr)

encoder.cpp: In function 'void encode(int, int, int, int*, int*)':
encoder.cpp:40:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   40 |  for(int i = 0; i < size(x); i += 3) {
      |                 ~~^~~~~~~~~

decoder.cpp: In function 'void decode(int, int)':
decoder.cpp:23:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   23 |  for(int i = 0; i < size(x); i += 3) {
      |                 ~~^~~~~~~~~

• Subtask 1: 25 / 25
• Subtask 2: 25 / 25
• Subtask 3: 25 / 25
• Subtask 4: 25 / 25