#include <bits/stdc++.h>
using namespace std;
int n, m;
typedef vector<int> vi;
typedef pair<int,int> ii;
struct node{
int depth = -1;
int low;
int parent;
bool vis = false;
bool isArti = false;
vi adj;
};
vector<unordered_set<int> > biconnected;
stack<int> s; ///this is only needed for biconnected components
///note: this will ignore single nodes with no edges
static node g[200005];
int rootChildren = 0;
void dfs(int u){
if(g[u].depth == -1) g[u].depth = g[g[u].parent].depth + 1;
g[u].low = g[u].depth;
g[u].vis = true;
for(int i = 0;i < g[u].adj.size();i++){
int v = g[u].adj[i];
if(!g[v].vis){
g[v].parent = u;
if(g[u].depth == 0) rootChildren++;
s.push(u); ///s traces the path of tree traversal
dfs(v);
g[u].low = min(g[u].low,g[v].low);
if(g[v].low >= g[u].depth){
g[u].isArti = true;
g[u].low = min(g[u].low,g[v].low);
unordered_set<int> newSet;
int nn;
biconnected.push_back(newSet); ///create new biconnected component
do{
assert(!s.empty());
nn = s.top();
s.pop();
biconnected.back().insert(nn);
}while(nn != u);
}
}
else if(v != g[u].parent){
g[u].low = min(g[u].low,g[v].depth); ///g[v].depth not num!!!!!!
}
s.push(u);
}
}
struct node2{
long long sz;
long long dp = 0;
bool isArti = false;
bool vis = false;
int r;
int p = -1;
vi adj;
};
vector<node2> bct; ///block-cut tree
long long root = -1;
void dp(int u){
if(bct[u].vis) return;
bct[u].vis = true;
bct[u].dp = bct[u].sz;
bct[u].r = root;
for(int i = 0;i < bct[u].adj.size();i++){
int v = bct[u].adj[i];
if(bct[v].vis) continue;
bct[v].p = u;
dp(v);
bct[u].dp += bct[v].dp;
}
}
int main()
{
cin >> n >> m;
ii edges[m];
for(int i = 0;i < m;i++){
int a, b;
cin >> a >> b;
a--;
b--;
g[a].adj.push_back(b);
g[b].adj.push_back(a);
edges[i] = ii(a,b);
}
for(int i = 0;i < n;i++){
if(!g[i].vis){
rootChildren = 0;
g[i].depth = 0;
dfs(i);
if(rootChildren > 1) g[i].isArti = true;
else g[i].isArti = false; ///this line is needed
}
}
unordered_map<int,int> artis;
for(int i = 0;i < n;i++){
if(g[i].isArti){
artis[i] = bct.size();
node2 nn;
nn.sz = 1;
nn.isArti = true;
bct.push_back(nn);
}
}
for(int i = 0;i < biconnected.size();i++){
node2 nn;
nn.sz = biconnected[i].size();
nn.isArti = false;
for(unordered_set<int>::iterator it = biconnected[i].begin();it != biconnected[i].end();it++){
if(artis.find(*it) != artis.end()){
nn.adj.push_back(artis[*it]);
bct[artis[*it]].adj.push_back(bct.size());
nn.sz--;
}
}
bct.push_back(nn);
}
for(int i = 0;i < bct.size();i++){
root = i;
dp(i);
}
long long ans = 0ll;
for(int i = 0;i < bct.size();i++){
vector<long long> branches;
vector<long long> branchStart;
long long total = 0ll;
for(int j = 0;j < bct[i].adj.size();j++){
if(bct[i].adj[j] != bct[i].p){
branches.push_back(bct[bct[i].adj[j]].dp);
branchStart.push_back(bct[bct[i].adj[j]].sz);
}
}
if(bct[i].p >= 0){
branches.push_back(bct[bct[i].r].dp - bct[i].dp);
branchStart.push_back(bct[bct[i].p].sz);
}
for(int j = 0;j < branches.size();j++) total += branches[j];
long long extra = 0ll;
if(!bct[i].isArti) extra = max(0ll,(long long)(bct[i].adj.size())-2);
for(int j = 0;j < branches.size();j++){
///branch1 to self or neighbor articulation point to branch2
ans += branches[j] * (total - branches[j]) * (bct[i].sz);
///branch to self to self or self to self to branch
ans += 2 * (bct[i].sz) * (bct[i].sz - 1) * branches[j];
if(bct[i].isArti){
///direct branch to self to same branch(not reverse) or its reverse
ans += 2ll * bct[i].sz * branchStart[j] * (branches[j] - branchStart[j]);
///direct branch to self to direct or its reverse
ans += bct[i].sz * (branchStart[j]) * (branchStart[j] - 1);
}
}
///self to self to self
ans += (bct[i].sz) * (bct[i].sz - 1) * (bct[i].sz - 2);
}
cout << ans;
}
Compilation message
count_triplets.cpp: In function 'void dfs(int)':
count_triplets.cpp:24:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i = 0;i < g[u].adj.size();i++){
~~^~~~~~~~~~~~~~~~~
count_triplets.cpp: In function 'void dp(int)':
count_triplets.cpp:70:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i = 0;i < bct[u].adj.size();i++){
~~^~~~~~~~~~~~~~~~~~~
count_triplets.cpp: In function 'int main()':
count_triplets.cpp:113:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i = 0;i < biconnected.size();i++){
~~^~~~~~~~~~~~~~~~~~~~
count_triplets.cpp:126:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i = 0;i < bct.size();i++){
~~^~~~~~~~~~~~
count_triplets.cpp:132:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i = 0;i < bct.size();i++){
~~^~~~~~~~~~~~
count_triplets.cpp:136:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int j = 0;j < bct[i].adj.size();j++){
~~^~~~~~~~~~~~~~~~~~~
count_triplets.cpp:146:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int j = 0;j < branches.size();j++) total += branches[j];
~~^~~~~~~~~~~~~~~~~
count_triplets.cpp:149:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int j = 0;j < branches.size();j++){
~~^~~~~~~~~~~~~~~~~
count_triplets.cpp:147:19: warning: variable 'extra' set but not used [-Wunused-but-set-variable]
long long extra = 0ll;
^~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
9 ms |
8312 KB |
Output is correct |
2 |
Correct |
9 ms |
8160 KB |
Output is correct |
3 |
Correct |
9 ms |
8184 KB |
Output is correct |
4 |
Correct |
9 ms |
8184 KB |
Output is correct |
5 |
Correct |
9 ms |
8184 KB |
Output is correct |
6 |
Correct |
9 ms |
8184 KB |
Output is correct |
7 |
Incorrect |
9 ms |
8188 KB |
Output isn't correct |
8 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
9 ms |
8312 KB |
Output is correct |
2 |
Correct |
9 ms |
8160 KB |
Output is correct |
3 |
Correct |
9 ms |
8184 KB |
Output is correct |
4 |
Correct |
9 ms |
8184 KB |
Output is correct |
5 |
Correct |
9 ms |
8184 KB |
Output is correct |
6 |
Correct |
9 ms |
8184 KB |
Output is correct |
7 |
Incorrect |
9 ms |
8188 KB |
Output isn't correct |
8 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
223 ms |
33592 KB |
Output is correct |
2 |
Correct |
258 ms |
33536 KB |
Output is correct |
3 |
Correct |
333 ms |
41308 KB |
Output is correct |
4 |
Correct |
276 ms |
37688 KB |
Output is correct |
5 |
Correct |
285 ms |
37340 KB |
Output is correct |
6 |
Correct |
344 ms |
40960 KB |
Output is correct |
7 |
Correct |
357 ms |
40156 KB |
Output is correct |
8 |
Correct |
356 ms |
41504 KB |
Output is correct |
9 |
Correct |
359 ms |
38840 KB |
Output is correct |
10 |
Correct |
336 ms |
36800 KB |
Output is correct |
11 |
Correct |
243 ms |
32488 KB |
Output is correct |
12 |
Correct |
246 ms |
32332 KB |
Output is correct |
13 |
Correct |
215 ms |
31680 KB |
Output is correct |
14 |
Correct |
234 ms |
31312 KB |
Output is correct |
15 |
Correct |
151 ms |
24900 KB |
Output is correct |
16 |
Correct |
181 ms |
24672 KB |
Output is correct |
17 |
Correct |
11 ms |
8188 KB |
Output is correct |
18 |
Correct |
10 ms |
8184 KB |
Output is correct |
19 |
Correct |
13 ms |
8184 KB |
Output is correct |
20 |
Correct |
10 ms |
8184 KB |
Output is correct |
21 |
Correct |
10 ms |
8184 KB |
Output is correct |
22 |
Correct |
10 ms |
8184 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
12 ms |
8568 KB |
Output is correct |
2 |
Correct |
12 ms |
8568 KB |
Output is correct |
3 |
Correct |
13 ms |
8696 KB |
Output is correct |
4 |
Correct |
14 ms |
8696 KB |
Output is correct |
5 |
Correct |
11 ms |
8568 KB |
Output is correct |
6 |
Correct |
12 ms |
8568 KB |
Output is correct |
7 |
Correct |
12 ms |
8696 KB |
Output is correct |
8 |
Correct |
12 ms |
8568 KB |
Output is correct |
9 |
Correct |
12 ms |
8568 KB |
Output is correct |
10 |
Correct |
11 ms |
8568 KB |
Output is correct |
11 |
Correct |
12 ms |
8568 KB |
Output is correct |
12 |
Correct |
11 ms |
8568 KB |
Output is correct |
13 |
Correct |
11 ms |
8572 KB |
Output is correct |
14 |
Correct |
11 ms |
8568 KB |
Output is correct |
15 |
Correct |
11 ms |
8440 KB |
Output is correct |
16 |
Correct |
10 ms |
8308 KB |
Output is correct |
17 |
Correct |
11 ms |
8440 KB |
Output is correct |
18 |
Correct |
11 ms |
8440 KB |
Output is correct |
19 |
Correct |
11 ms |
8440 KB |
Output is correct |
20 |
Correct |
11 ms |
8440 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
371 ms |
49960 KB |
Output is correct |
2 |
Correct |
400 ms |
50008 KB |
Output is correct |
3 |
Correct |
374 ms |
49868 KB |
Output is correct |
4 |
Correct |
447 ms |
49916 KB |
Output is correct |
5 |
Correct |
379 ms |
49820 KB |
Output is correct |
6 |
Correct |
460 ms |
58296 KB |
Output is correct |
7 |
Correct |
428 ms |
55496 KB |
Output is correct |
8 |
Correct |
426 ms |
54256 KB |
Output is correct |
9 |
Correct |
409 ms |
52728 KB |
Output is correct |
10 |
Correct |
377 ms |
49952 KB |
Output is correct |
11 |
Correct |
379 ms |
49844 KB |
Output is correct |
12 |
Correct |
380 ms |
49844 KB |
Output is correct |
13 |
Correct |
371 ms |
49848 KB |
Output is correct |
14 |
Correct |
346 ms |
48160 KB |
Output is correct |
15 |
Correct |
296 ms |
38636 KB |
Output is correct |
16 |
Correct |
165 ms |
29888 KB |
Output is correct |
17 |
Correct |
242 ms |
41748 KB |
Output is correct |
18 |
Correct |
248 ms |
41556 KB |
Output is correct |
19 |
Correct |
279 ms |
41388 KB |
Output is correct |
20 |
Correct |
291 ms |
41500 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
15 ms |
8568 KB |
Output is correct |
2 |
Correct |
12 ms |
8568 KB |
Output is correct |
3 |
Incorrect |
14 ms |
8540 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
391 ms |
50128 KB |
Output is correct |
2 |
Correct |
399 ms |
49856 KB |
Output is correct |
3 |
Incorrect |
427 ms |
48820 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
9 ms |
8312 KB |
Output is correct |
2 |
Correct |
9 ms |
8160 KB |
Output is correct |
3 |
Correct |
9 ms |
8184 KB |
Output is correct |
4 |
Correct |
9 ms |
8184 KB |
Output is correct |
5 |
Correct |
9 ms |
8184 KB |
Output is correct |
6 |
Correct |
9 ms |
8184 KB |
Output is correct |
7 |
Incorrect |
9 ms |
8188 KB |
Output isn't correct |
8 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
9 ms |
8312 KB |
Output is correct |
2 |
Correct |
9 ms |
8160 KB |
Output is correct |
3 |
Correct |
9 ms |
8184 KB |
Output is correct |
4 |
Correct |
9 ms |
8184 KB |
Output is correct |
5 |
Correct |
9 ms |
8184 KB |
Output is correct |
6 |
Correct |
9 ms |
8184 KB |
Output is correct |
7 |
Incorrect |
9 ms |
8188 KB |
Output isn't correct |
8 |
Halted |
0 ms |
0 KB |
- |