#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define pb push_back
#define mp make_pair
typedef pair<int, int> ii;
const int mod = 1e9 + 7;
const int inf = 1e9;
int add(int x, int y) {
return (1ll * x + 1ll * y) % mod;
}
int del(int x, int y) {
return ((1ll * x - 1ll * y) % mod + mod) % mod;
}
int mul(int x, int y) {
return (1ll * x * 1ll * y) % mod;
}
const int N = 2e5 + 5;
int n, m, pSet[N], sz[N];
vector<int> graph[N];
int findSet(int u) {
//cout << u << "\n";
if(u == pSet[u]) return u;
else return pSet[u] = findSet(pSet[u]);
}
void unionSet(int u, int v) {
u = findSet(u), v = findSet(v);
if(u == v) return ;
sz[v] += sz[u];
pSet[u] = v;
}
bool vis[N];
vector<int> vec, gr[N];
void dfs(int u) {
vis[u] = 1;
vec.pb(u);
for(int i = 0; i < graph[u].size(); i++) {
int v = graph[u][i];
if(!vis[v])
dfs(v);
}
}
int main() {
cin.tie(0), ios_base::sync_with_stdio(0);
// freopen("test.inp", "r", stdin);
cin >> n >> m;
for(int i = 1; i <= n; i++)
pSet[i] = i, sz[i] = 1;
for(int i = 1; i <= m; i++) {
int u, v;
cin >> u >> v;
graph[u].pb(v);
}
for(int i = 1; i <= n; i++) {
if(graph[i].size() >= 2) {
for(int j = 0; j < graph[i].size() - 1; j++)
unionSet(graph[i][j], graph[i][j + 1]);
}
}
/* for(int i = 1; i <= n; i++) {
for(int j = 0; j < graph[i].size(); j++) {
int v = graph[i][j];
if(findSet(i) != findSet(v))
gr[findSet(i)].pb(findSet(v));
}
}
for(int i = 1; i <= n; i++) {
graph[i] = gr[i];
gr[i].clear();
}*/
for(int i = 1; i <= n; i++) {
if(!vis[i] && sz[findSet(i)] >= 2) {
vec.clear();
dfs(i);
for(int j = 0; j < vec.size() - 1; j++)
unionSet(vec[j], vec[j + 1]);
}
}
for(int i = 1; i <= n; i++) {
for(int j = 0; j < graph[i].size(); j++) {
int v = graph[i][j];
if(findSet(i) != findSet(v))
gr[findSet(i)].pb(findSet(v));
}
}
for(int i = 1; i <= n; i++)
graph[i] = gr[i];
memset(vis, 0, sizeof(vis));
long long total = 0;
for(int i = 1; i <= n; i++) {
if(!vis[findSet(i)]) {
vis[findSet(i)] = 1;
if(sz[findSet(i)] >= 2)
total += 1ll * sz[findSet(i)] * (sz[findSet(i)] - 1);
else
total += graph[findSet(i)].size();
}
}
cout << total;
}
Compilation message
friends.cpp: In function 'void dfs(int)':
friends.cpp:54:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i = 0; i < graph[u].size(); i++) {
~~^~~~~~~~~~~~~~~~~
friends.cpp: In function 'int main()':
friends.cpp:74:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int j = 0; j < graph[i].size() - 1; j++)
~~^~~~~~~~~~~~~~~~~~~~~
friends.cpp:93:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int j = 0; j < vec.size() - 1; j++)
~~^~~~~~~~~~~~~~~~
friends.cpp:98:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int j = 0; j < graph[i].size(); j++) {
~~^~~~~~~~~~~~~~~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
10 ms |
9852 KB |
Output is correct |
2 |
Correct |
11 ms |
9944 KB |
Output is correct |
3 |
Correct |
10 ms |
9976 KB |
Output is correct |
4 |
Correct |
10 ms |
9976 KB |
Output is correct |
5 |
Correct |
10 ms |
9880 KB |
Output is correct |
6 |
Correct |
11 ms |
9912 KB |
Output is correct |
7 |
Correct |
11 ms |
9976 KB |
Output is correct |
8 |
Correct |
11 ms |
9976 KB |
Output is correct |
9 |
Correct |
13 ms |
9976 KB |
Output is correct |
10 |
Correct |
11 ms |
9976 KB |
Output is correct |
11 |
Correct |
11 ms |
9976 KB |
Output is correct |
12 |
Correct |
11 ms |
9976 KB |
Output is correct |
13 |
Correct |
11 ms |
9976 KB |
Output is correct |
14 |
Correct |
11 ms |
9976 KB |
Output is correct |
15 |
Correct |
10 ms |
9976 KB |
Output is correct |
16 |
Incorrect |
11 ms |
9976 KB |
Output isn't correct |
17 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
13 ms |
10104 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
60 ms |
11172 KB |
Output is correct |
2 |
Incorrect |
121 ms |
15180 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |