To store the data in a more compact form, it's necessary to understand the data so you can look for more compact representations of the information it represents. And for now, that isn't clear (to me).

I set up a small set of input ranges--of both the normal--$start <= $end type; and the inverted $end < $start type; and then tried to make sense of the numbers returned by num_ranges_containing(). And I cannot.

I input these ranges:

my @ranges = (
    [ 0, 5 ], [ 1, 6 ], [ 2, 7 ], [ 3, 8 ], [ 4, 9 ], [ 5, 10 ],
    [ 5, 0 ], [ 6, 1 ], [ 7, 2 ], [ 8, 3 ], [ 9, 4 ], [ 10, 5 ],
);
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And then asked for the counts containing the ranges: [0,3], [1,4], ...., [7,10], and as the returns didn't add up, I did a simple plot:

c:\test>861961
------                0.. 5
 ------               1.. 6
  ------              2.. 7
   ------             3.. 8
    ------            4.. 9
     ------           5..10
      -----           5.. 0
-      ----           6.. 1
--      ---           7.. 2
---      --           8.. 3
----      -           9.. 4
-----                10.. 5

----                  0.. 3     range: 0 .. 3 is contained by 1 ranges
 ----                 1.. 4     range: 1 .. 4 is contained by 4 ranges
  ----                2.. 5     range: 2 .. 5 is contained by 4 ranges
   ----               3.. 6     range: 3 .. 6 is contained by 3 ranges
    ----              4.. 7     range: 4 .. 7 is contained by 3 ranges
     ----             5.. 8     range: 5 .. 8 is contained by 3 ranges
      ----            6.. 9     range: 6 .. 9 is contained by 2 ranges
       ----           7..10     range: 7 .. 10 is contained by 1 range
+s
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Looking at just a couple:

• [0,3] returns 1;

  But to my eyes, it appears to be contained by at least: the first, and last two input ranges?

• [1,4] returns 4;

  But only appears to be contained by the first two, and last input ranges?

How am I misinterpreting the data?