//https://oj.uz/problem/view/JOI14_friends
#include<bits/stdc++.h>
const int N = 1e5 + 5;
using namespace std;
vector <int> adj[N];
int n, m, pset[N], siz[N];
long long ans;
bool check[N];
int findset(int i) {return ((pset[i] == i) ? i : pset[i] = findset(pset[i]));}
bool unionset(int i, int j){
i = findset(i); j = findset(j);
if (i == j) return false;
siz[j] += siz[i];
pset[i] = j;
return true;
}
int main(){
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
cin >> n >> m;
for (int i = 1; i <= m; i++){
int u, v; cin >> u >> v;
adj[u].push_back(v);
}
for (int i = 1; i <= n; i++) pset[i] = i, siz[i] = 1;
for (int u = 1; u <= n; u++){
if ((int)adj[u].size() >= 2){
int x = adj[u][0]; check[x] = true;
for (int i = 1; i < (int)adj[u].size(); i++){
int v = adj[u][i];
check[v] = true;
unionset(x, v);
}
}
}
queue <int> mq;
for (int i = 1; i <= n; i++) if (check[i]) mq.push(i);
while (mq.size()){
int u = mq.front(); mq.pop();
for (int i = 0; i < (int)adj[u].size(); i++){
int v = adj[u][i];
if (!check[v]) check[v] = true, mq.push(v);
unionset(u, v);
}
}
for (int i = 1; i <= n; i++) if (pset[i] == i) ans += 1LL * siz[i] * (siz[i] - 1);
for (int i = 1; i <= n; i++) if (pset[i] == i && siz[i] == 1) ans += (int)adj[i].size();
cout << ans << "\n";
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
3 ms |
2680 KB |
Output is correct |
| 2 |
Correct |
3 ms |
2680 KB |
Output is correct |
| 3 |
Correct |
4 ms |
2836 KB |
Output is correct |
| 4 |
Correct |
3 ms |
2836 KB |
Output is correct |
| 5 |
Correct |
3 ms |
2836 KB |
Output is correct |
| 6 |
Correct |
3 ms |
2836 KB |
Output is correct |
| 7 |
Correct |
3 ms |
2836 KB |
Output is correct |
| 8 |
Correct |
4 ms |
2836 KB |
Output is correct |
| 9 |
Correct |
3 ms |
2852 KB |
Output is correct |
| 10 |
Correct |
3 ms |
2852 KB |
Output is correct |
| 11 |
Correct |
3 ms |
2904 KB |
Output is correct |
| 12 |
Correct |
3 ms |
2904 KB |
Output is correct |
| 13 |
Correct |
3 ms |
2904 KB |
Output is correct |
| 14 |
Correct |
3 ms |
2908 KB |
Output is correct |
| 15 |
Correct |
3 ms |
2908 KB |
Output is correct |
| 16 |
Correct |
3 ms |
2908 KB |
Output is correct |
| 17 |
Correct |
4 ms |
2980 KB |
Output is correct |
| 18 |
Correct |
4 ms |
2980 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
7 ms |
3036 KB |
Output is correct |
| 2 |
Correct |
5 ms |
3036 KB |
Output is correct |
| 3 |
Correct |
13 ms |
3164 KB |
Output is correct |
| 4 |
Correct |
63 ms |
3932 KB |
Output is correct |
| 5 |
Correct |
31 ms |
3932 KB |
Output is correct |
| 6 |
Correct |
60 ms |
4444 KB |
Output is correct |
| 7 |
Correct |
4 ms |
4444 KB |
Output is correct |
| 8 |
Correct |
6 ms |
4444 KB |
Output is correct |
| 9 |
Correct |
10 ms |
4444 KB |
Output is correct |
| 10 |
Correct |
16 ms |
4444 KB |
Output is correct |
| 11 |
Correct |
50 ms |
4448 KB |
Output is correct |
| 12 |
Correct |
7 ms |
4448 KB |
Output is correct |
| 13 |
Correct |
4 ms |
4448 KB |
Output is correct |
| 14 |
Correct |
4 ms |
4448 KB |
Output is correct |
| 15 |
Correct |
6 ms |
4448 KB |
Output is correct |
| 16 |
Correct |
12 ms |
4448 KB |
Output is correct |
| 17 |
Correct |
48 ms |
4448 KB |
Output is correct |
| 18 |
Correct |
4 ms |
4448 KB |
Output is correct |
| 19 |
Correct |
4 ms |
4448 KB |
Output is correct |
| 20 |
Correct |
51 ms |
4448 KB |
Output is correct |
| 21 |
Correct |
4 ms |
4448 KB |
Output is correct |
| 22 |
Correct |
4 ms |
4448 KB |
Output is correct |
| 23 |
Correct |
6 ms |
4448 KB |
Output is correct |
| 24 |
Correct |
5 ms |
4448 KB |
Output is correct |
| 25 |
Correct |
4 ms |
4448 KB |
Output is correct |
| 26 |
Correct |
4 ms |
4448 KB |
Output is correct |
| 27 |
Correct |
4 ms |
4448 KB |
Output is correct |
| 28 |
Correct |
4 ms |
4448 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
59 ms |
4448 KB |
Output is correct |
| 2 |
Correct |
136 ms |
6892 KB |
Output is correct |
| 3 |
Correct |
91 ms |
9300 KB |
Output is correct |
| 4 |
Correct |
46 ms |
9500 KB |
Output is correct |
| 5 |
Correct |
25 ms |
9500 KB |
Output is correct |
| 6 |
Correct |
74 ms |
11988 KB |
Output is correct |
| 7 |
Correct |
68 ms |
15632 KB |
Output is correct |
| 8 |
Correct |
78 ms |
18080 KB |
Output is correct |
| 9 |
Correct |
41 ms |
18388 KB |
Output is correct |
| 10 |
Correct |
58 ms |
20688 KB |
Output is correct |
| 11 |
Correct |
87 ms |
23368 KB |
Output is correct |
| 12 |
Correct |
84 ms |
26056 KB |
Output is correct |
| 13 |
Correct |
36 ms |
26764 KB |
Output is correct |
| 14 |
Correct |
54 ms |
26764 KB |
Output is correct |
| 15 |
Correct |
21 ms |
27588 KB |
Output is correct |
| 16 |
Correct |
5 ms |
27588 KB |
Output is correct |
| 17 |
Correct |
4 ms |
27588 KB |
Output is correct |
| 18 |
Correct |
85 ms |
31276 KB |
Output is correct |
| 19 |
Correct |
83 ms |
33580 KB |
Output is correct |
| 20 |
Correct |
46 ms |
33852 KB |
Output is correct |
| 21 |
Correct |
23 ms |
33852 KB |
Output is correct |
| 22 |
Correct |
5 ms |
33852 KB |
Output is correct |
| 23 |
Correct |
28 ms |
33852 KB |
Output is correct |
| 24 |
Correct |
58 ms |
36644 KB |
Output is correct |
| 25 |
Correct |
38 ms |
39100 KB |
Output is correct |
| 26 |
Correct |
40 ms |
41824 KB |
Output is correct |
| 27 |
Correct |
96 ms |
43088 KB |
Output is correct |
| 28 |
Correct |
41 ms |
43248 KB |
Output is correct |
| 29 |
Correct |
52 ms |
44360 KB |
Output is correct |
| 30 |
Correct |
115 ms |
47360 KB |
Output is correct |
| 31 |
Correct |
55 ms |
47360 KB |
Output is correct |
| 32 |
Correct |
45 ms |
49380 KB |
Output is correct |
| 33 |
Correct |
46 ms |
50524 KB |
Output is correct |
| 34 |
Correct |
50 ms |
50876 KB |
Output is correct |
| 35 |
Correct |
39 ms |
52896 KB |
Output is correct |
| 36 |
Correct |
39 ms |
55072 KB |
Output is correct |
| 37 |
Correct |
39 ms |
55072 KB |
Output is correct |
