弦图的PERFECT ELIMINATION点排列
/*
* INIT: g[][]置为邻接矩阵;
* CALL: cardinality(n);tag[i]为排列中第i个点的标号;
*/
const int V = 10010;
int tag[V], g[V][V], deg[V], vis[V];
void cardinality(int n)
{
int i, j, k;
memset(deg, 0, sizeof(deg));
memset(vis, 0, sizeof(vis));
for (i = n - 1; i >= 0; i--)
{
for (j = 0, k = -1; j < n; j++)
{
if (0 == vis[j])
{
if (k == -1 || deg[j] > deg[k])
{
k = j;
}
}
}
vis[k] = 1, tag[i] = k;
for (j = 0; j<n; j++)
{
if (0 == vis[j] && g[k][j])
{
deg[j]++;
}
}
}
return ;
}