* docs: document the complexity of ordered_map operations
ordered_map stores its elements in a std::vector in insertion order and
has no lookup index, so emplace, operator[], at, find, count, erase, and
insert are all linear scans. The documentation stated no complexity for
any operation, neither in ordered_map.md nor in ordered_json.md.
Add a per-operation complexity table and note the consequence: building
or parsing an ordered_json object of n keys is O(n^2). Measured with
-O2 -DNDEBUG for parsing a flat object of n keys, ordered_json is 5x
slower than json at n=2000 and 54x slower at n=16000, with the timings
quadrupling per doubling of n. Cross-reference the table from
ordered_json.md and from the object order page, which recommends
ordered_json without mentioning the cost.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* docs: move the Complexity section after Member functions
scripts/check_structure.py enforces a fixed section order for pages under
docs/mkdocs/docs/api, in which Complexity comes after Member functions.
The section had been placed right after Iterator invalidation, which made
ci_test_build_documentation fail with structure/section_order.
No content change beyond the move; the table columns are realigned to the
narrower content.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
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Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Niels LohmannandGitHub
