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//------------------------------------------------------------------------------
// CAMD/Source/camd_postorder: post-order the assembly tree from CAMD
//------------------------------------------------------------------------------
// CAMD, Copyright (c) 2007-2022, Timothy A. Davis, Yanqing Chen, Patrick R.
// Amestoy, and Iain S. Duff. All Rights Reserved.
// SPDX-License-Identifier: BSD-3-clause
//------------------------------------------------------------------------------
/* Perform a postordering (via depth-first search) of an assembly tree. */
#include "camd_internal.h"
Int CAMD_postorder
(
Int j, /* start at node j, a root of the assembly tree */
Int k, /* on input, next node is the kth node */
Int n, /* normal nodes 0 to n-1, place-holder node n */
Int head [], /* head of link list of children of each node */
Int next [], /* next[i] is the next child after i in link list */
Int post [], /* postordering, post [k] = p if p is the kth node */
Int stack [] /* recursion stack */
)
{
int i, p, top = 0 ;
stack [0] = j ; /* place j on the stack, maybe place-holder node n */
while (top >= 0) /* while (stack is not empty) */
{
p = stack [top] ; /* p = top of stack */
i = head [p] ; /* i = youngest child of p */
if (i == -1)
{
top-- ; /* p has no unordered children left */
if (p != n)
{
/* node p is the kth postordered node. Do not postorder the
* place-holder node n, which is the root of a subtree
* containing all dense and empty nodes. */
post [k++] = p ;
}
}
else
{
head [p] = next [i] ; /* remove i from children of p */
stack [++top] = i ; /* start dfs on child node i */
}
}
return (k) ;
}
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