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Java time-based map/cache with expiring keys [closed]
Do any of you know of a Java Map or similar standard data store that automatically purges entries after a given timeout? This means aging, where the old expired entries “age-out” automatically.
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What are the differences between segment trees, interval trees, binary indexed trees and range trees
...mption for one dimension:
Segment tree - O(n logn) preprocessing time, O(k+logn) query time, O(n logn) space
Interval tree - O(n logn) preprocessing time, O(k+logn) query time, O(n) space
Range tree - O(n logn) preprocessing time, O(k+logn) query time, O(n) space
Binary Indexed tree - O(n logn) pr...
How to generate all permutations of a list?
...'re using an older Python (<2.6) for some reason or are just curious to know how it works, here's one nice approach, taken from http://code.activestate.com/recipes/252178/:
def all_perms(elements):
if len(elements) <=1:
yield elements
else:
for perm in all_perms(eleme...
Why does this iterative list-growing code give IndexError: list assignment index out of range?
...t do:
j = list(i)
Alternatively, if you wanted to use the Python list like an array in other languages, then you could pre-create a list with its elements set to a null value (None in the example below), and later, overwrite the values in specific positions:
i = [1, 2, 3, 5, 8, 13]
j = [None] * ...
Change the name of a key in dictionary
I want to change the key of an entry in a Python dictionary.
15 Answers
15
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Getting a slice of keys from a map
Is there any simpler/nicer way of getting a slice of keys from a map in Go?
6 Answers
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how to calculate binary search complexity
... search hence it is log(n) algorithm. Since I am not from a mathematics background I am not able to relate to it. Can somebody explain it in a little more detail? does it have to do something with the logarithmic series?
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Maximum single-sell profit
Suppose we are given an array of n integers representing stock prices on a single day. We want to find a pair (buyDay, sellDay) , with buyDay ≤ sellDay , such that if we bought the stock on buyDay and sold it on sellDay , we would maximize our profit.
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Calculate difference in keys contained in two Python dictionaries
...on dictionaries - dictA and dictB . I need to find out if there are any keys which are present in dictB but not in dictA . What is the fastest way to go about it?
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Encoding Javascript Object to Json string
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Unless the variable k is defined, that's probably what's causing your trouble. Something like this will do what you want:
var new_tweets = { };
new_tweets.k = { };
new_tweets.k.tweet_id = 98745521;
new_tweets.k.user_id = 54875;
new_tweets.k...