1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
| #include <cstdio>
#include <vector>
#define pb push_back
using namespace std;
template <class Type>
void read (Type &x)
{
char c;
bool flag = false;
while ((c = getchar()) < '0' || c > '9')
c == '-' && (flag = true);
x = c - '0';
while ((c = getchar()) >= '0' && c <= '9')
x = (x << 1) + (x << 3) + c - '0';
flag && (x = ~x + 1);
}
template <class Type, class ...rest>
void read (Type &x, rest &...y) { read(x), read(y...); }
template <class Type>
void write (Type x)
{
x < 0 && (putchar('-'), x = ~x + 1);
x > 9 && (write(x / 10), 0);
putchar('0' + x % 10);
}
const int N = 1e4 + 10;
int n, m, d[N], p[N], f[N], g[N];
vector <int> e[N];
int stmp, dfn[N], low[N];
void tarjan (int u)
{
int k = 0;
dfn[u] = low[u] = ++stmp;
for (int v : e[u]) if (v ^ p[u])
if (!dfn[v])
{
d[v] = d[u] + 1; p[v] = u;
tarjan(v);
low[u] = min(low[u], low[v]);
if (low[v] > dfn[u]) k = max(k, g[v] + 1);
}
else low[u] = min(low[u], dfn[v]);
for (int v : e[u]) if (dfn[v] > dfn[u] && p[v] ^ u)
{
int s = 1, t = 0;
for (int i = v; i ^ u; i = p[i])
t = max(t, s + g[i]), s += f[i] + 1;
f[u] += s;
for (int i = v, c = s; i ^ u; i = p[i])
c -= f[i] + 1, t = max(t, c + g[i]);
k = max(k, t - s);
}
g[u] = f[u] + k;
}
int main ()
{
read(n, m);
for (int a, b; m; --m)
read(a, b), e[a].pb(b), e[b].pb(a);
tarjan(1);
write(g[1]);
return 0;
}
|