I would use a simple hash, with the PIDs as the keys, and the full lines (or possibly the line without the PID) as values: 
(
...,
7510 => "7510  5044  /usr/bin/grep",
7512 => "7512  4333  /usr/bin/egrep",
7515 => "7515  7508  sh",
7516 => "7516  7515  <defunct>"
)

[download]
It is then very easy to read the PPID of the defunct process (7515), and from there look at the parent (7515 is its key), find the grand parent ID (7508) and look at the grand parent, and so on.

No need for a more complicated data structure, and this will be very fast.

In reply to Re: Help parsing this data by Laurent_R
in thread Help parsing this data by cspctec

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.