Given a list of current directories and a list of selected directories, return the selected directories after summarizing.
Example:
The entire directories:
/a/b/x.txt
/a/b/p.txt
/a/c
/a/d/y.txt
/a/d/z.txtThe selected directories:
/a/d/y.txt
/a/d/z.txt
/a/b/p.txtThis problem asks you to summarize a list of selected directory paths against the full set of available paths. A common approach is to normalize the paths, then use prefix checks, sorting, a hash set, or a trie to merge items that can be represented at a higher directory level while preserving the meaning of the selection. The key is to detect redundant nested paths and return a clean summarized list.
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