[cut point] ZOJ 1119 SPF

#include<cstdio>
#include<vector>
#include<memory>
using namespace std;

const int MaxN = 500;
const int root = 1;

vector<int>v[MaxN];
int a[MaxN];
int D[MaxN];
int cut[MaxN];
int c[MaxN];

void dfs(int k, int f, int d)
{
int i;
int t;
int tot(0);
vector<int> :: iterator it;
a[k] = d;
D[k] = d;
c[k] = 1;

for (it=v[k].begin(); it!=v[k].end(); ++it)
{
t = *it;

if (c[t] == 1)
{
a[k] = a[k] < D[t] ? a[k] : D[t];
}

if (c[t] == 0)
{
dfs(t, k, d + 1);
++tot;

a[k] = a[k] < a[t] ? a[k] : a[t];

if ((k == root && tot > 1) || (k != root && a[t] >= D[k]))
{
++cut[k];
}
}
}

c[k] = 2;
}

int main(void)
{
int x;
int y;
int i;
int n;
int case_num(1);
bool find;

scanf("%d", &x);

while (1)
{
for (i=0; i<MaxN; ++i)
{
v[i].clear();
}
n = 0;

while (x != 0)
{
scanf("%d", &y);

v[x].push_back(y);
v[y].push_back(x);
++n;

scanf("%d", &x);
}

memset(cut, 0, sizeof(cut));
memset(c, 0, sizeof(c));
dfs(root, root, 0);

find = false;
for (i=1; i<=n; ++i)
{
if (cut[i] != 0)
{
find = true;
break;
}
}

printf("Network #%d/n", case_num);
++case_num;

if (find)
{
for (; i<=n; ++i)
{
if (cut[i] != 0)
{
printf("  SPF node %d leaves %d subnets/n", i, cut[i]+1);
}
}
}
else
{
printf("  No SPF nodes/n");
}

scanf("%d", &x);

if (x == 0)
{
break;
}

printf("/n");
}

return 0;
}