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Unique (non-repeating) random numbers in O(1)?
I'd like to generate unique random numbers between 0 and 1000 that never repeat (i.e. 6 doesn't show up twice), but that doesn't resort to something like an O(N) search of previous values to do it. Is this possible?
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Proper stack and heap usage in C++?
I've been programming for a while but It's been mostly Java and C#. I've never actually had to manage memory on my own. I recently began programming in C++ and I'm a little confused as to when I should store things on the stack and when to store them on the heap.
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What does O(log n) mean exactly?
I am learning about Big O Notation running times and amortized times. I understand the notion of O(n) linear time, meaning that the size of the input affects the growth of the algorithm proportionally...and the same goes for, for example, quadratic time O(n2) etc..even algorithms, such as permu...
How can building a heap be O(n) time complexity?
...?
Often, answers to these questions focus on the difference between siftUp and siftDown. Making the correct choice between siftUp and siftDown is critical to get O(n) performance for buildHeap, but does nothing to help one understand the difference between buildHeap and heapSort in general. Indeed, ...
What's the fastest algorithm for sorting a linked list?
...estigate whether you can sort it in-place, stably, its worst-case behavior and so on.
Simon Tatham, of Putty fame, explains how to sort a linked list with merge sort. He concludes with the following comments:
Like any self-respecting sort algorithm, this has running time O(N log N). Because th...
What do the terms “CPU bound” and “I/O bound” mean?
What do the terms "CPU bound" and "I/O bound" mean?
11 Answers
11
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psql: could not connect to server: No such file or directory (Mac OS X)
...master has exited.).
SOLUTION: This fixed the issue--I deleted this file, and then everything worked!
/usr/local/var/postgres/postmaster.pid
--
and here is how I figured out why this needed to be deleted.
I used the following command to see if there were any PG processes running. for me ther...
Is there a Max function in SQL Server that takes two values like Math.Max in .NET?
...f @val1 > @val2
return @val1
return isnull(@val2,@val1)
end
... and you would call it like so ...
SELECT o.OrderId, dbo.InlineMax(o.NegotiatedPrice, o.SuggestedPrice)
FROM Order o
share
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How can I create a Makefile for C projects with SRC, OBJ, and BIN subdirectories?
...ry object,
it often uses the wrong source (as you discovered with file1.o and file2.o)
it tries to build executables instead of stopping at objects, and
the name of the target (foo.o) is not what the rule will actually produce (obj/foo.o).
I suggest the following:
OBJECTS := $(SOURCES:$(SRCDI...
How does a hash table work?
... in layman's terms.
Let's assume you want to fill up a library with books and not just stuff them in there, but you want to be able to easily find them again when you need them.
So, you decide that if the person that wants to read a book knows the title of the book and the exact title to boot, the...