/*
* CXSPARSE: a Concise Sparse Matrix package - Extended.
* Copyright (c) 2006-2009, Timothy A. Davis.
* http://www.cise.ufl.edu/research/sparse/CXSparse
*
* CXSparse is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* CXSparse is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this Module; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "cs.h"
/* post order a forest */
CS_INT *cs_post (const CS_INT *parent, CS_INT n)
{
CS_INT j, k = 0, *post, *w, *head, *next, *stack ;
if (!parent) return (NULL) ; /* check inputs */
post = cs_malloc (n, sizeof (CS_INT)) ; /* allocate result */
w = cs_malloc (3*n, sizeof (CS_INT)) ; /* get workspace */
if (!w || !post) return (cs_idone (post, NULL, w, 0)) ;
head = w ; next = w + n ; stack = w + 2*n ;
for (j = 0 ; j < n ; j++) head [j] = -1 ; /* empty linked lists */
for (j = n-1 ; j >= 0 ; j--) /* traverse nodes in reverse order*/
{
if (parent [j] == -1) continue ; /* j is a root */
next [j] = head [parent [j]] ; /* add j to list of its parent */
head [parent [j]] = j ;
}
for (j = 0 ; j < n ; j++)
{
if (parent [j] != -1) continue ; /* skip j if it is not a root */
k = cs_tdfs (j, k, head, next, post, stack) ;
}
return (cs_idone (post, NULL, w, 1)) ; /* success; free w, return post */
}