#include "meetings.h"
#include <algorithm>
#include <iostream>
#include <numeric>
#include <cassert>
#include <random>
#include <vector>
typedef long long llong;
const int MAXN = 2000 + 10;
const int INF = 1e9;
int n;
int sz[MAXN];
bool bl[MAXN];
int perm[MAXN];
bool alreadyAdded[MAXN];
std::vector <int> g[MAXN];
std::vector <int> c[MAXN];
std::vector <int> real[MAXN];
std::mt19937 rng(69420);
void removeEdge(int u, int v)
{
if (u == -1 || v == -1)
{
return;
}
for (int &x : g[u])
{
if (x == v)
{
std::swap(x, g[u].back());
g[u].pop_back();
break;
}
}
for (int &x : g[v])
{
if (x == u)
{
std::swap(x, g[v].back());
g[v].pop_back();
break;
}
}
}
void addEdge(int u, int v)
{
if (u == -1 || v == -1)
{
return;
}
g[u].push_back(v);
g[v].push_back(u);
}
void calcSize(int node, int par)
{
sz[node] = 1;
for (const int &u : g[node])
{
if (u == par || bl[u])
{
continue;
}
calcSize(u, node);
sz[node] += sz[u];
}
}
int findCentroid(int node, int par, int compSz)
{
for (const int &u : g[node])
{
if (!bl[u] && u != par && sz[u] > compSz / 2)
{
return findCentroid(u, node, compSz);
}
}
return node;
}
int decompose(int node)
{
calcSize(node, -1);
int cntr = findCentroid(node, -1, sz[node]);
bl[cntr] = true;
for (const int &u : g[cntr])
{
if (bl[u])
{
continue;
}
c[cntr].push_back(decompose(u));
real[cntr].push_back(u);
}
return cntr;
}
void search(int node, int added)
{
bool addedEdge = false;
for (int i = 0 ; i < c[node].size() ; i += 2)
{
if (i == c[node].size() - 1)
{
int res = Query(node, real[node][i], added);
if (res == node)
{
continue;
}
if (res != node && res != real[node][i] && res != added)
{
removeEdge(node, real[node][i]);
addEdge(node, res);
addEdge(res, real[node][i]);
addEdge(res, added);
alreadyAdded[res] = true;
return;
}
if (res == added)
{
removeEdge(node, real[node][i]);
if (!addedEdge)
{
addEdge(node, added);
addedEdge = true;
}
addEdge(real[node][i], added);
continue;
}
if (res == real[node][i])
{
search(c[node][i], added);
return;
}
assert(false);
}
int res = Query(real[node][i], real[node][i + 1], added);
if (res == node)
{
continue;
}
if (res == added)
{
int res2 = Query(node, real[node][i], added);
if (res == res2)
{
removeEdge(node, real[node][i]);
if (!addedEdge)
{
addEdge(node, added);
addedEdge = true;
}
addEdge(real[node][i], added);
} else
{
removeEdge(node, real[node][i + 1]);
if (!addedEdge)
{
addEdge(node, added);
addedEdge = true;
}
addEdge(real[node][i + 1], added);
}
return;
}
if (res == real[node][i])
{
search(c[node][i], added);
return;
}
if (res == real[node][i + 1])
{
search(c[node][i], added);
return;
}
if (res != node && res != real[node][i] && res != added)
{
int res2 = Query(node, real[node][i], added);
if (res == res2)
{
removeEdge(node, real[node][i]);
addEdge(node, res);
addEdge(res, real[node][i]);
addEdge(res, added);
alreadyAdded[res] = true;
} else
{
removeEdge(node, real[node][i + 1]);
addEdge(node, res);
addEdge(res, real[node][i + 1]);
addEdge(res, added);
alreadyAdded[res] = true;
}
return;
}
assert(false);
}
if (!addedEdge)
{
addEdge(node, added);
}
}
void Solve(int N)
{
n = N;
std::iota(perm, perm + n, 0);
std::shuffle(perm, perm + n, rng);
for (int i = 0 ; i < n ; ++i)
{
g[i].clear();
c[i].clear();
real[i].clear();
}
g[perm[0]].push_back(perm[1]);
g[perm[1]].push_back(perm[0]);
for (int i = 2 ; i < n ; ++i)
{
if (alreadyAdded[perm[i]])
{
continue;
}
for (int j = 0 ; j < n ; ++j)
{
c[j].clear();
real[j].clear();
std::shuffle(g[j].begin(), g[j].end(), rng);
}
std::fill(bl, bl + n, false);
int root = decompose(perm[0]);
search(root, perm[i]);
}
for (int i = 0 ; i < n ; ++i)
{
for (const int &u : g[i])
{
if (i < u)
{
Bridge(i, u);
}
}
}
}
Compilation message
meetings.cpp: In function 'void search(int, int)':
meetings.cpp:113:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
113 | for (int i = 0 ; i < c[node].size() ; i += 2)
| ~~^~~~~~~~~~~~~~~~
meetings.cpp:115:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
115 | if (i == c[node].size() - 1)
| ~~^~~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
600 KB |
Output is correct |
| 2 |
Incorrect |
1 ms |
600 KB |
Wrong Answer [4] |
| 3 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
600 KB |
Output is correct |
| 2 |
Incorrect |
1 ms |
600 KB |
Wrong Answer [4] |
| 3 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
600 KB |
Output is correct |
| 2 |
Incorrect |
1 ms |
600 KB |
Wrong Answer [4] |
| 3 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
240 ms |
262144 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
