#include <cstdio>
#include <vector>
using namespace std;
struct disj{
int pa[100005], sz[100005];
void init(int n){
for(int i=1; i<=n; i++) pa[i] = i, sz[i] = 1;
}
int find(int x){
if(pa[x] == x) return x;
return pa[x] = find(pa[x]);
}
int uni(int p, int q){
p = find(p);
q = find(q);
if(p == q) return 0;
pa[q] = p;
sz[p] += sz[q];
return 1;
}
}disj;
bool vis[100005];
int n,m;
vector<int> g[100005];
int main(){
scanf("%d %d",&n,&m);
disj.init(n);
for (int i=0; i<m; i++) {
int x,y;
scanf("%d %d",&x,&y);
g[x].push_back(y);
}
for (int i=1; i<=n; i++) {
for (int j=0; j+1<g[i].size(); j++) {
disj.uni(g[i][j],g[i][j+1]);
}
}
for (int i=1; i<=n; i++) {
if(disj.sz[disj.find(i)] != 1 && !g[i].empty()){
disj.uni(i,g[i][0]);
}
}
long long ret = 0;
for (int i=1; i<=n; i++) {
if(!vis[disj.find(i)]){
vis[disj.find(i)] = 1;
ret += 1ll * disj.sz[disj.find(i)] * (disj.sz[disj.find(i)] - 1);
}
}
for (int i=1; i<=n; i++) {
for (int &j : g[i]){
if(disj.find(i) != disj.find(j)) ret++;
}
}
printf("%lld",ret);
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
4436 KB |
Output is correct |
2 |
Correct |
0 ms |
4436 KB |
Output is correct |
3 |
Correct |
0 ms |
4436 KB |
Output is correct |
4 |
Correct |
1 ms |
4436 KB |
Output is correct |
5 |
Correct |
0 ms |
4436 KB |
Output is correct |
6 |
Correct |
0 ms |
4436 KB |
Output is correct |
7 |
Correct |
0 ms |
4436 KB |
Output is correct |
8 |
Correct |
0 ms |
4436 KB |
Output is correct |
9 |
Correct |
0 ms |
4436 KB |
Output is correct |
10 |
Correct |
0 ms |
4436 KB |
Output is correct |
11 |
Incorrect |
0 ms |
4436 KB |
Output isn't correct |
12 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
0 ms |
4436 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
58 ms |
5492 KB |
Output is correct |
2 |
Incorrect |
110 ms |
7208 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |