#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define N 100000
int *ej[N], eo[N];
void append(int i, int j) {
int o = eo[i]++;
if (o >= 2 && (o & o - 1) == 0)
ej[i] = (int *) realloc(ej[i], o * 2 * sizeof *ej[i]);
ej[i][o] = j;
}
int ds[N], sz[N];
int find(int i) {
return ds[i] < 0 ? i : (ds[i] = find(ds[i]));
}
void join(int i, int j) {
i = find(i);
j = find(j);
if (i == j)
return;
if (ds[i] > ds[j])
ds[i] = j, sz[j] += sz[i];
else {
if (ds[i] == ds[j])
ds[i]--;
ds[j] = i, sz[i] += sz[j];
}
}
char visited[N];
void dfs(int i) {
int o;
if (visited[i])
return;
visited[i] = 1;
for (o = eo[i]; o--; ) {
int j = ej[i][o];
join(i, j);
dfs(j);
}
}
int main() {
int n, m, i, j, j_, o;
long long ans;
scanf("%d%d", &n, &m);
for (i = 0; i < n; i++)
ej[i] = (int *) malloc(2 * sizeof *ej[i]);
while (m--) {
scanf("%d%d", &i, &j), i--, j--;
append(i, j);
}
memset(ds, -1, n * sizeof *ds);
for (i = 0; i < n; i++)
sz[i] = 1;
for (i = 0; i < n; i++)
if (eo[i] >= 2) {
j_ = ej[i][0];
for (o = eo[i]; o--; ) {
j = ej[i][o];
join(j, j_);
}
for (o = eo[i]; o--; ) {
j = ej[i][o];
dfs(j);
}
}
ans = 0;
for (i = 0; i < n; i++)
if (ds[i] < 0)
ans += sz[i] == 1 ? eo[i] : (long long) sz[i] * (sz[i] - 1);
printf("%lld\n", ans);
return 0;
}
Compilation message
friends.c: In function 'append':
friends.c:12:23: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
12 | if (o >= 2 && (o & o - 1) == 0)
| ~~^~~
friends.c: In function 'main':
friends.c:57:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
57 | scanf("%d%d", &n, &m);
| ^~~~~~~~~~~~~~~~~~~~~
friends.c:61:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
61 | scanf("%d%d", &i, &j), i--, j--;
| ^~~~~~~~~~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Correct |
0 ms |
212 KB |
Output is correct |
4 |
Correct |
1 ms |
212 KB |
Output is correct |
5 |
Correct |
0 ms |
212 KB |
Output is correct |
6 |
Correct |
0 ms |
212 KB |
Output is correct |
7 |
Correct |
0 ms |
212 KB |
Output is correct |
8 |
Correct |
1 ms |
340 KB |
Output is correct |
9 |
Correct |
1 ms |
212 KB |
Output is correct |
10 |
Correct |
0 ms |
212 KB |
Output is correct |
11 |
Correct |
0 ms |
212 KB |
Output is correct |
12 |
Correct |
0 ms |
212 KB |
Output is correct |
13 |
Correct |
0 ms |
212 KB |
Output is correct |
14 |
Correct |
1 ms |
212 KB |
Output is correct |
15 |
Correct |
0 ms |
212 KB |
Output is correct |
16 |
Correct |
0 ms |
212 KB |
Output is correct |
17 |
Correct |
0 ms |
212 KB |
Output is correct |
18 |
Correct |
0 ms |
212 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
468 KB |
Output is correct |
2 |
Correct |
1 ms |
468 KB |
Output is correct |
3 |
Correct |
8 ms |
812 KB |
Output is correct |
4 |
Correct |
37 ms |
1660 KB |
Output is correct |
5 |
Correct |
25 ms |
1384 KB |
Output is correct |
6 |
Correct |
43 ms |
2064 KB |
Output is correct |
7 |
Correct |
1 ms |
340 KB |
Output is correct |
8 |
Correct |
4 ms |
340 KB |
Output is correct |
9 |
Correct |
7 ms |
596 KB |
Output is correct |
10 |
Correct |
12 ms |
1004 KB |
Output is correct |
11 |
Correct |
60 ms |
2108 KB |
Output is correct |
12 |
Correct |
5 ms |
724 KB |
Output is correct |
13 |
Correct |
2 ms |
468 KB |
Output is correct |
14 |
Correct |
2 ms |
468 KB |
Output is correct |
15 |
Correct |
3 ms |
596 KB |
Output is correct |
16 |
Correct |
8 ms |
852 KB |
Output is correct |
17 |
Correct |
44 ms |
2020 KB |
Output is correct |
18 |
Correct |
2 ms |
468 KB |
Output is correct |
19 |
Correct |
2 ms |
852 KB |
Output is correct |
20 |
Correct |
45 ms |
2040 KB |
Output is correct |
21 |
Correct |
2 ms |
468 KB |
Output is correct |
22 |
Correct |
2 ms |
468 KB |
Output is correct |
23 |
Correct |
3 ms |
596 KB |
Output is correct |
24 |
Correct |
2 ms |
468 KB |
Output is correct |
25 |
Correct |
1 ms |
468 KB |
Output is correct |
26 |
Correct |
2 ms |
468 KB |
Output is correct |
27 |
Correct |
2 ms |
468 KB |
Output is correct |
28 |
Correct |
2 ms |
468 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
43 ms |
1608 KB |
Output is correct |
2 |
Correct |
71 ms |
9608 KB |
Output is correct |
3 |
Correct |
70 ms |
9568 KB |
Output is correct |
4 |
Correct |
37 ms |
6372 KB |
Output is correct |
5 |
Correct |
18 ms |
5972 KB |
Output is correct |
6 |
Correct |
60 ms |
7244 KB |
Output is correct |
7 |
Correct |
64 ms |
8316 KB |
Output is correct |
8 |
Correct |
62 ms |
8024 KB |
Output is correct |
9 |
Correct |
36 ms |
6708 KB |
Output is correct |
10 |
Correct |
46 ms |
7192 KB |
Output is correct |
11 |
Correct |
66 ms |
9600 KB |
Output is correct |
12 |
Correct |
71 ms |
10148 KB |
Output is correct |
13 |
Correct |
38 ms |
6492 KB |
Output is correct |
14 |
Correct |
53 ms |
4564 KB |
Output is correct |
15 |
Correct |
21 ms |
6060 KB |
Output is correct |
16 |
Correct |
5 ms |
5460 KB |
Output is correct |
17 |
Correct |
4 ms |
4948 KB |
Output is correct |
18 |
Correct |
70 ms |
9304 KB |
Output is correct |
19 |
Correct |
77 ms |
9308 KB |
Output is correct |
20 |
Correct |
43 ms |
6732 KB |
Output is correct |
21 |
Correct |
24 ms |
5988 KB |
Output is correct |
22 |
Correct |
4 ms |
5332 KB |
Output is correct |
23 |
Correct |
24 ms |
2252 KB |
Output is correct |
24 |
Correct |
43 ms |
6560 KB |
Output is correct |
25 |
Correct |
28 ms |
6476 KB |
Output is correct |
26 |
Correct |
41 ms |
12764 KB |
Output is correct |
27 |
Correct |
76 ms |
11100 KB |
Output is correct |
28 |
Correct |
37 ms |
6488 KB |
Output is correct |
29 |
Correct |
42 ms |
6492 KB |
Output is correct |
30 |
Correct |
72 ms |
9488 KB |
Output is correct |
31 |
Correct |
35 ms |
6740 KB |
Output is correct |
32 |
Correct |
31 ms |
6372 KB |
Output is correct |
33 |
Correct |
31 ms |
6488 KB |
Output is correct |
34 |
Correct |
34 ms |
6508 KB |
Output is correct |
35 |
Correct |
36 ms |
6480 KB |
Output is correct |
36 |
Correct |
38 ms |
10720 KB |
Output is correct |
37 |
Correct |
37 ms |
6512 KB |
Output is correct |