25 lines
784 B
C
25 lines
784 B
C
#include "cs.h"
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/* depth-first search and postorder of a tree rooted at node j */
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int cs_tdfs (int j, int k, int *head, const int *next, int *post, int *stack)
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{
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int i, p, top = 0 ;
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if (!head || !next || !post || !stack) return (-1) ; /* check inputs */
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stack [0] = j ; /* place j on the stack */
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while (top >= 0) /* while (stack is not empty) */
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{
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p = stack [top] ; /* p = top of stack */
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i = head [p] ; /* i = youngest child of p */
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if (i == -1)
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{
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top-- ; /* p has no unordered children left */
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post [k++] = p ; /* node p is the kth postordered node */
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}
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else
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{
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head [p] = next [i] ; /* remove i from children of p */
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stack [++top] = i ; /* start dfs on child node i */
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}
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}
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return (k) ;
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}
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