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Why does Dijkstra's algorithm use decrease-key?

... the total number of heap dequeues is n. Each node will have decrease-key called on it potentially once for each edge leading into it, so the total number of decrease-keys done is at most m. This gives a runtime of (n Te + n Td + m Tk), where Tk is the time required to call decrease-key. So what ...
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Adding 'serial' to existing column in Postgres

... You can also use START WITH to start a sequence from a particular point, although setval accomplishes the same thing, as in Euler's answer, eg, SELECT MAX(a) + 1 FROM foo; CREATE SEQUENCE foo_a_seq START WITH 12345; -- replace ...
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Find XOR of all numbers in a given range

You are given a large range [a,b] where 'a' and 'b' can be typically between 1 and 4,000,000,000 inclusive. You have to find out the XOR of all the numbers in the given range. ...
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Foreign keys in mongo?

...ot 'tables' but collections. Documents are grouped inside Collections. You can have any kind of document – with any kind of data – in a single collection. Basically, in a NoSQL database it is up to you to decide how to organise the data and its relations, if there are any. What Mongoid and Mong...
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When do I need to use a semicolon vs a slash in Oracle SQL?

...L object, running a PL/SQL anonymous block, and executing a DML statement) can be picked out more easily by eye. Also, if you eventually move to something like Ant for deployment it will simplify the definition of targets to have a consistent statement delimiter. ...
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Skip a submodule during a Maven build

... Sure, this can be done using profiles. You can do something like the following in your parent pom.xml. ... <modules> <module>module1</module> <module>module2</module> ... </m...
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What's the difference between an exclusive lock and a shared lock?

... I wrote this answer down because I thought this would be a fun (and fitting) analogy: Think of a lockable object as a blackboard (lockable) in a class room containing a teacher (writer) and many students (readers). While a teacher is writing somethin...
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Difference between size_t and std::size_t

... common mistake is to assume size_t is the same as unsigned int, which can lead to programming errors,[3][4] when moving from 32 to 64-bit architecture, for example. According to the 1999 ISO C standard (C99), size_t is an unsigned integer type of at least 16 bits. And the rest ...
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What's the longest possible worldwide phone number I should consider in SQL varchar(length) for phon

...char(100) if you're only storing 20 characters in each, err on the side of caution and just make it 50. share | improve this answer | follow | ...
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What is the purpose of AsQueryable()?

Is the purpose of AsQueryable() just so you can pass around an IEnumerable to methods that might expect IQueryable , or is there a useful reason to represent IEnumerable as IQueryable ? For example, is it supposed to be for cases like this: ...