Commit Graph

17 Commits

Author SHA1 Message Date
Fred Drake f2928eb017 Fix typo in comment. 2002-11-13 14:38:17 +00:00
Raymond Hettinger a853cc6647 Added __all__. 2002-10-30 06:15:53 +00:00
Tim Peters 5f7617b5f6 Fixed misspelling in comment. 2002-08-11 18:28:09 +00:00
Tim Peters 469cdad822 Whitespace normalization. 2002-08-08 20:19:19 +00:00
Guido van Rossum 3c8dd0c6e7 Simplify heapreplace() -- there's no need for an explicit test for
empty heap, since heap[0] raises the appropriate IndexError already.
2002-08-07 18:58:11 +00:00
Tim Peters 6681de2455 _siftup(): __le__ is now the only comparison operator used on array
elements.
2002-08-03 19:20:16 +00:00
Tim Peters 0cd53a6c37 Added new heapreplace(heap, item) function, to pop (and return) the
currently-smallest value, and add item, in one gulp.  See the second
N-Best algorithm in the test suite for a natural use.
2002-08-03 10:10:10 +00:00
Tim Peters 657fe38241 Large code rearrangement to use better algorithms, in the sense of needing
substantially fewer array-element compares.  This is best practice as of
Kntuh Volume 3 Ed 2, and the code is actually simpler this way (although
the key idea may be counter-intuitive at first glance!  breaking out of
a loop early loses when it costs more to try to get out early than getting
out early saves).
Also added a comment block explaining the difference and giving some real
counts; demonstrating that heapify() is more efficient than repeated
heappush(); and emphasizing the obvious point thatlist.sort() is more
efficient if what you really want to do is sort.
2002-08-03 09:56:52 +00:00
Tim Peters aa7d24319e Minor fiddling, including a simple class to implement a heap iterator
in the test file.  I have docs for heapq.heapify ready to check in, but
Jack appears to have left behind a stale lock in the Doc/lib directory.
2002-08-03 02:11:26 +00:00
Guido van Rossum fbb299226d Augment credits. 2002-08-02 22:01:37 +00:00
Tim Peters 28c25527c2 Hmm! I thought I checked this in before! Oh well.
Added new heapify() function, which transforms an arbitrary list into a
heap in linear time; that's a fundamental tool for using heaps in real
life <wink>.

Added heapyify() test.  Added a "less naive" N-best algorithm to the test
suite, and noted that this could actually go much faster (building on
heapify()) if we had max-heaps instead of min-heaps (the iterative method
is appropriate when all the data isn't known in advance, but when it is
known in advance the tradeoffs get murkier).
2002-08-02 21:48:06 +00:00
Guido van Rossum 4b48d6b37c Add a PEP-263-style encoding turd^H^H^H^Hdeclaration, because there's
a c-cedilla in one of the docstrings.
2002-08-02 20:23:56 +00:00
Tim Peters 62abc2f6ce heappop(): Added comments; simplified and sped the code. 2002-08-02 20:09:14 +00:00
Tim Peters a0b3a00bc5 heappop(): Use "while True" instead of "while 1". 2002-08-02 19:45:37 +00:00
Tim Peters d9ea39db84 Don't use true division where int division was intended. For that matter,
don't use division at all.
2002-08-02 19:16:44 +00:00
Guido van Rossum 37c3b2788b Add Kevin O'Connor, author of the heapq code. 2002-08-02 16:50:58 +00:00
Guido van Rossum 0a82438859 Adding the heap queue algorithm, per discussion in python-dev last
week.
2002-08-02 16:44:32 +00:00