Simple solution: take all the begin and end points of the ranges. Sort them. Loop over the resulting list. Any time you don't have the end point of range immediately following the begin point of the same range, you have overlap. How to deal with ranges sharing endpoints is left as an exercise to the reader.

In your case, the resulting after sorting is (marking begin points with a capital letter, end points with a lowercase letter) 

1(A), 10(a), 11(B), 15(C), 20(b), 21(D), 25(c), 25(E), 30(d), 35(e).

[download]
So, c overlaps b, d overlaps c, e overlaps d, and whether e overlaps c is something you'll have to further specify.

In reply to Re: overlap between ranges by JavaFan
in thread overlap between ranges by hifirock

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.