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QOJ
ID | 题目 | 提交者 | 结果 | 用时 | 内存 | 语言 | 文件大小 | 提交时间 | 测评时间 |
---|---|---|---|---|---|---|---|---|---|
#519813 | #5670. Group Guests | ucup-team1198 | WA | 367ms | 201840kb | C++20 | 9.8kb | 2024-08-15 03:09:59 | 2024-08-15 03:09:59 |
Judging History
answer
#include <map>
#include <set>
#include <array>
#include <cmath>
#include <deque>
#include <bitset>
#include <random>
#include <string>
#include <vector>
#include <cassert>
#include <complex>
#include <iomanip>
#include <iostream>
#include <algorithm>
#include <unordered_map>
#include <unordered_set>
using namespace std;
const int MAXN = 4'000'100;
vector<pair<int, int>> G[MAXN];
int tin[MAXN];
int tup[MAXN];
int ttime = 0;
vector<int> stack;
vector<vector<int>> edge_comps;
int edge_comp_id[MAXN];
int used[MAXN];
vector<int> vertices;
void dfs_dot(int v, int p) {
vertices.emplace_back(v);
tin[v] = ttime;
tup[v] = ttime;
++ttime;
used[v] = 1;
for (auto [u, i] : G[v]) {
if (i == p)
continue;
if (used[u] == 0) {
int stack_sz = stack.size();
stack.emplace_back(i);
dfs_dot(u, i);
if (tup[u] >= tin[v]) {
// falls off
edge_comps.emplace_back();
while (stack.size() > stack_sz) {
edge_comps.back().emplace_back(stack.back());
stack.pop_back();
}
}
tup[v] = min(tup[v], tup[u]);
} else if (used[u] == 1) {
// edge up
stack.emplace_back(i);
tup[v] = min(tup[v], tin[u]);
} else {
// not interesting
}
}
used[v] = 2;
}
vector<int> Gtree[MAXN];
int up[MAXN];
int tree_sz[MAXN];
void dfs_tree(int v, int p) {
up[v] = p;
for (int u : Gtree[v]) {
if (u == p)
continue;
dfs_tree(u, v);
tree_sz[v] += tree_sz[u];
}
}
int id[MAXN];
vector<pair<int, int>> Gright[MAXN];
int cur_edges = 0;
int n;
int get_tree_sz(int from, int to) {
if (up[to] == from)
return tree_sz[to];
return cur_edges - tree_sz[from];
}
bool check_even(int comp_id, int v) {
return get_tree_sz(comp_id + n, v) % 2 == 0;
}
bool check_triangle(vector<int> vertices) {
sort(vertices.begin(), vertices.end(), [](int a, int b) {
return G[a].size() < G[b].size();
});
for (int i = 0; i < vertices.size(); ++i)
id[vertices[i]] = i;
for (int v : vertices) {
for (auto [u, i] : G[v]) {
if (id[u] > id[v]) {
Gright[v].emplace_back(u, i);
}
}
}
vector<bool> state(vertices.size(), false);
for (int v : vertices) {
for (auto [u, i1] : Gright[v])
state[id[u]] = true;
for (auto [u, i1] : Gright[v]) {
for (auto [x, i2] : Gright[u]) {
if (state[id[x]]) {
// triangle!
// v, u, x
int comp_id = edge_comp_id[i1];
bool ok = check_even(comp_id, v) && check_even(comp_id, u) && check_even(comp_id, x);
if (ok)
return true;
}
}
}
for (auto [u, i1] : Gright[v])
state[id[u]] = false;
}
return false;
}
pair<int, int> solve(int N, vector<pair<int, int>> edges) {
ttime = 0;
n = N;
int m = edges.size();
for (int i = 0; i < m; ++i) {
auto [a, b] = edges[i];
G[a].emplace_back(b, i);
G[b].emplace_back(a, i);
}
fill(used, used + n, 0);
int ans_edge = 0;
int ans_hedg = 0;
vector<vector<int>> conn_comps;
for (int i = 0; i < n; ++i) {
if (used[i])
continue;
dfs_dot(i, -1);
conn_comps.emplace_back(vertices);
vertices.clear();
}
for (int i = 0; i < edge_comps.size(); ++i) {
//////cerr << "edge_comp " << i << ": ";
for (int j : edge_comps[i]) {
//////cerr << j << ' ';
edge_comp_id[j] = i;
}
//////cerr << '\n';
}
for (int i = 0; i < m; ++i) {
auto [a, b] = edges[i];
int j = n + edge_comp_id[i];
Gtree[j].emplace_back(a);
Gtree[j].emplace_back(b);
Gtree[a].emplace_back(j);
Gtree[b].emplace_back(j);
}
for (int i = 0; i < n + edge_comps.size(); ++i) {
sort(Gtree[i].begin(), Gtree[i].end());
Gtree[i].resize(unique(Gtree[i].begin(), Gtree[i].end()) - Gtree[i].begin());
}
for (int i = 0; i < n + edge_comps.size(); ++i)
tree_sz[i] = 0;
for (int i = 0; i < edge_comps.size(); ++i)
tree_sz[n + i] = edge_comps[i].size();
vector<int> kek(edge_comps.size());
for (int j = 0; j < conn_comps.size(); ++j) {
auto& vertices = conn_comps[j];
int root = vertices.front();
dfs_tree(root, -1);
cur_edges = 0;
for (int v : vertices)
cur_edges += G[v].size();
cur_edges /= 2;
if (cur_edges % 2 == 0)
continue;
// check triangle
if (check_triangle(vertices)) {
continue;
}
// check hedgehog
bool can_hedge = false;
for (int v : vertices) {
int rem_deg = 0;
for (int u : Gtree[v]) {
kek[u - n] = 0;
}
for (auto [u, i] : G[v]) {
int j = edge_comp_id[i];
++kek[j];
}
for (int u : Gtree[v]) {
int edges = get_tree_sz(v, u) - kek[u - n];
rem_deg += kek[u - n] - edges % 2;
}
if (rem_deg >= 3)
can_hedge = true;
}
if (can_hedge) {
++ans_hedg;
} else {
++ans_edge;
}
}
for (int i = 0; i < n + edge_comps.size(); ++i)
Gtree[i].clear();
for (int i = 0; i < n; ++i) {
Gright[i].clear();
G[i].clear();
}
edge_comps.clear();
return make_pair(ans_edge, ans_hedg);
}
bool all_comps_even(int n, vector<pair<int, int>> edges) {
vector<vector<int>> G(n);
for (auto [a, b] : edges) {
G[a].emplace_back(b);
G[b].emplace_back(a);
}
vector<bool> used(n, false);
for (int i = 0; i < n; ++i) {
if (used[i])
continue;
vector<int> cur;
int q_sz = 0;
used[i] = true;
cur.emplace_back(i);
while (q_sz < cur.size()) {
int v = cur[q_sz];
++q_sz;
for (int u : G[v]) {
if (!used[u]) {
used[u] = true;
cur.emplace_back(u);
}
}
}
int total = 0;
for (int v : cur) {
//cerr << v << '(' << G[v].size() << ')' << ' ';
total += G[v].size();
}
//cerr << '\n';
total /= 2;
//cerr << total << '\n';
if (total % 2 == 1)
return false;
}
return true;
}
pair<int, int> solve_dumb(int n, vector<pair<int, int>> edges) {
int m = edges.size();
vector<vector<int>> G(n);
vector<vector<bool>> matrix(n, vector<bool>(n, false));
for (auto [a, b] : edges) {
G[a].emplace_back(b);
G[b].emplace_back(a);
matrix[a][b] = true;
matrix[b][a] = true;
}
auto rem_edge = [](vector<pair<int, int>> edges, pair<int, int> edge) {
int i = 0;
pair<int, int> edge_rev(edge.second, edge.first);
while (edges[i] != edge && edges[i] != edge_rev)
++i;
edges.erase(edges.begin() + i);
return edges;
};
int ans_edge = 0;
int ans_hedg = 0;
vector<bool> used(n, false);
for (int i = 0; i < n; ++i) {
if (used[i])
continue;
vector<int> cur;
int q_sz = 0;
cur.emplace_back(i);
used[i] = true;
while (q_sz < cur.size()) {
int v = cur[q_sz];
++q_sz;
for (int u : G[v]) {
if (!used[u]) {
used[u] = true;
cur.emplace_back(u);
}
}
}
vector<pair<int, int>> cur_edges;
for (int v : cur) {
for (int u : G[v]) {
if (v < u)
cur_edges.emplace_back(v, u);
}
}
if (cur_edges.size() % 2 == 0)
continue;
// 1) check triangle
bool have = false;
for (int v : cur) {
for (int u : G[v]) {
for (int x : G[u]) {
if (x == v)
continue;
if (!matrix[v][x])
continue;
//cerr << v << ' ' << u << ' ' << x << '\n';
auto kek = rem_edge(rem_edge(rem_edge(cur_edges, make_pair(u, v)), make_pair(v, x)), make_pair(u, x));
if (all_comps_even(n, kek))
have = true;
}
}
}
if (have)
continue;
// 2) check hedge
for (int v : cur) {
for (int i = 0; i < G[v].size(); ++i) {
for (int j = i + 1; j < G[v].size(); ++j) {
for (int k = j + 1; k < G[v].size(); ++k) {
int a = G[v][i];
int b = G[v][j];
int c = G[v][k];
auto kek = rem_edge(rem_edge(rem_edge(cur_edges, make_pair(v, a)), make_pair(v, b)), make_pair(v, c));
if (all_comps_even(n, kek))
have = true;
}
}
}
}
if (have) {
++ans_hedg;
} else {
++ans_edge;
}
}
return make_pair(ans_edge, ans_hedg);
}
//#define STRESS
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
#ifdef STRESS
for (int _ = 0; _ < 100100; ++_) {
int n = rand() % 5 + 2;
int m = rand() % (n * (n - 1) / 2) + 1;
set<pair<int, int>> kek;
vector<pair<int, int>> edges(m);
for (int i = 0; i < m; ++i) {
int a = rand() % (n - 1);
int b = a + rand() % (n - a - 1) + 1;
while (kek.count(make_pair(a, b))) {
a = rand() % (n - 1);
b = a + rand() % (n - a - 1) + 1;
}
kek.emplace(a, b);
edges[i] = make_pair(a, b);
}
auto ans1 = solve(n, edges);
auto ans2 = solve_dumb(n, edges);
if (ans1 != ans2) {
cerr << "BUG!!!\n";
cerr << m << ' ' << n << '\n';
for (auto [a, b] : edges)
cerr << a + 1 << ' ' << b + 1 << '\n';
cerr << "wrong: ";
cerr << ans1.first << ' ' << ans1.second << '\n';
cerr << "right: ";
cerr << ans2.first << ' ' << ans2.second << "\n\n";
}
}
#else
int m;
cin >> m >> n;
vector<pair<int, int>> edges(m);
for (int i = 0; i < m; ++i) {
int a, b;
cin >> a >> b;
--a;
--b;
edges[i] = make_pair(a, b);
}
auto [ans1, ans2] = solve(n, edges);
cout << ans1 << ' ' << ans2 << '\n';
#endif
return 0;
}
详细
Test #1:
score: 100
Accepted
time: 12ms
memory: 17924kb
input:
2 4 1 2 3 4
output:
2 0
result:
ok single line: '2 0'
Test #2:
score: 0
Accepted
time: 7ms
memory: 15932kb
input:
2 3 1 2 3 1
output:
0 0
result:
ok single line: '0 0'
Test #3:
score: 0
Accepted
time: 8ms
memory: 17984kb
input:
5 5 1 2 2 3 2 4 5 2 5 4
output:
0 0
result:
ok single line: '0 0'
Test #4:
score: -100
Wrong Answer
time: 367ms
memory: 201840kb
input:
999990 666660 1 2 1 5 1 7 1 8 1 9 1 10 2 4 2 6 2 9 2 10 3 4 4 8 5 8 6 7 6 10 11 13 11 15 11 20 12 17 12 19 13 16 13 19 14 16 14 19 15 17 15 18 16 17 16 19 17 18 17 20 21 26 21 27 21 29 22 26 22 27 22 29 23 26 23 30 24 26 24 28 25 27 25 30 26 27 26 29 28 29 31 33 31 40 32 35 33 35 33 37 33 38 33 39 3...
output:
383 5252
result:
wrong answer 1st lines differ - expected: '383 523', found: '383 5252'