#include <bits/stdc++.h>
using namespace std;
#define m_p make_pair
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define fi first
#define se second
typedef long long ll;
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
mt19937 rnf(2106);
const int N = 400005;
int n, m;
vector<vector<int> > adj;
vector<bool> visited;
vector<int> tin, low;
int timer;
vector<pair<int, int> > s;
vector<vector<pair<int, int> > > v;
void dfs(int v, int p = -1) {
visited[v] = true;
tin[v] = low[v] = timer++;
int children=0;
for (int to : adj[v]) {
if (to == p) continue;
if (visited[to]) {
low[v] = min(low[v], tin[to]);
if (tin[to] < tin[v])
s.push_back(m_p(v, to));
} else {
s.push_back(m_p(v, to));
dfs(to, v);
low[v] = min(low[v], low[to]);
if ((low[to] >= tin[v] && p != -1) || (p == -1 && children > 1))
{
vector<pair<int, int> > vv;
while (s.back() != m_p(v, to))
{
vv.push_back(s.back());
s.pop_back();
}
vv.push_back(s.back());
s.pop_back();
::v.push_back(vv);
}
++children;
}
}
}
void find_cutpoints() {
timer = 0;
visited.assign(n, false);
tin.assign(n, -1);
low.assign(n, -1);
for (int i = 0; i < n; ++i) {
if (!visited[i])
{
dfs (i);
if (!s.empty())
v.push_back(s);
}
}
}
vector<int> g[N];
int q[N];
void dfs1(int x, int p)
{
if (x < n)
q[x] = 1;
for (int i = 0; i < g[x].size(); ++i)
{
int h = g[x][i];
if (h == p)
continue;
dfs1(h, x);
q[x] += q[h];
}
}
ll ans;
void dfs2(int x, int p, int r)
{
for (int i = 0; i < g[x].size(); ++i)
{
int h = g[x][i];
if (h == p)
continue;
dfs2(h, x, r);
}
if (x >= n)
{
for (int i = 0; i < g[x].size(); ++i)
{
int h = g[x][i];
int qq;
if (h == p)
qq = (q[r] - q[x]);
else
qq = q[h];
ans -= qq * 1LL * (qq - 1) * 1LL * (sz(g[x]) - 1);
}
}
}
void solv()
{
cin >> n >> m;
adj.assign(n, {});
for (int i = 0; i < m; ++i)
{
int x, y;
cin >> x >> y;
--x;
--y;
adj[x].push_back(y);
adj[y].push_back(x);
}
find_cutpoints();
int k = n;
for (int i = 0; i < sz(v); ++i)
{
set<int> s;
for (int j = 0; j < sz(v[i]); ++j)
{
s.insert(v[i][j].fi);
s.insert(v[i][j].se);
}
for (auto it = s.begin(); it != s.end(); ++it)
{
g[*it].push_back(k);
g[k].push_back(*it);
}
k++;
}
for (int i = 0; i < k; ++i)
{
if (!q[i])
{
dfs1(i, i);
ans += (q[i] * 1LL * (q[i] - 1) * 1LL * (q[i] - 2));
dfs2(i, i, i);
}
}
cout << ans << "\n";
}
int main()
{
#ifdef SOMETHING
freopen("input.txt", "r", stdin);
//freopen("output.txt", "w", stdout);
#endif // SOMETHING
ios_base::sync_with_stdio(false), cin.tie(0);
int tt = 1;
//cin >> tt;
while (tt--)
{
solv();
}
return 0;
}
Compilation message
count_triplets.cpp: In function 'void dfs1(int, int)':
count_triplets.cpp:75:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
75 | for (int i = 0; i < g[x].size(); ++i)
| ~~^~~~~~~~~~~~~
count_triplets.cpp: In function 'void dfs2(int, int, int)':
count_triplets.cpp:88:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
88 | for (int i = 0; i < g[x].size(); ++i)
| ~~^~~~~~~~~~~~~
count_triplets.cpp:98:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
98 | for (int i = 0; i < g[x].size(); ++i)
| ~~^~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
568 ms |
1048576 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
568 ms |
1048576 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
108 ms |
39876 KB |
Output is correct |
| 2 |
Correct |
93 ms |
39956 KB |
Output is correct |
| 3 |
Runtime error |
528 ms |
1048576 KB |
Execution killed with signal 9 |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
7 ms |
9960 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
99 ms |
29944 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
6 ms |
9812 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
83 ms |
29900 KB |
Output is correct |
| 2 |
Incorrect |
102 ms |
29872 KB |
Output isn't correct |
| 3 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
568 ms |
1048576 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
568 ms |
1048576 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
