> However, I don't see how you would know the locations in this problem?
Well, that's just from the blogpost itself:
> Application 2: Finding the Missing Number
> You are given an array A of n - 1 integers which are in the range between 1 and n. All numbers appear exactly once, except one number, which is missing. Find this missing number.
We can "find the missing number", but we don't know where to "put" the missing number. If you want to put the "missing number" back into the sequence, you still need to know the location to put it into from some other mechanism. (Ex: hard drive #5 failed, so you know to put the number into slot#5).
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Application 4 starts to get into "partitioning", which is getting dangerously close to sparse parity-check matrix and LDPC graphs.
Ah, do you mean that solving the problem described in the blog-post helps actually using erasure coding, since it requires knowing which parts are missing?
However, I don't see how you would know the locations in this problem?
Maybe you can elaborate on how this problem relates to erasure coding?