Questions tagged [algorithm-analysis]
Analyzing an algorithm to determine its time and space performance.
110 questions
2votes
7answers
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Why is big O notation an asymptotic notation/analysis?
An asymptote in mathematics represents a value (line) to which the observed function constantly approaches. In other words, as the value of X increases towards infinity, i.e. decreases towards minus ...
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21votes
6answers
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Using a different algorithm depending on the size of the input
I recently finished a course on advanced algorithms, and another on complexity & computability theory, and in the past few days my mind has been somewhat preoccupied by this question. Why don't we ...
- 345
3votes
1answer
310views
Algorithms: How do I sum O(n) and O(mlog(n)) together?
I'm doing a running time analysis using the aggregate method and I'm a bit confused about what would be the result in this case. I have some intuition in inferring that it would be O(mlog(n)) but I'm ...
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1vote
3answers
190views
How can I mix this grid to guarantee it being solvable in X minimum steps?
Note: This question is not about this particular instance of this grid with these exact words, but about any combination of words. I am programming a puzzle game where you have to arrange a grid of ...
32votes
5answers
49kviews
Algorithms: How do I sum O(n) and O(nlog(n)) together?
I have the follow algorithm which finds duplicates and removes them: public static int numDuplicatesB(int[] arr) { Sort.mergesort(arr); int numDups = 0; for (int i = 1; i < arr.length; ...
1vote
1answer
115views
Some questions about shortest-path algorithms
I'm trying to understand why anyone would prefer Floyd-Warshal over Dijkstra: Dijkstra gives a correct result, using an understandable system, combined with backtracking. Floyd-Warshal makes an ...
- 1,846
23votes
4answers
4kviews
When speaking, how can I say that the time complexity order of an algorithm is O(N log N)?
What term can I use to describe something with O(N log N) complexity? For example: O(1): Constant O(log N): Logarithmic O(N): Linear O(N log N): ?????? O(N2): Quadratic O(N3): Cubic
0votes
2answers
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Calculating time complexity of a code snippet
I am trying to calculate the time complexity of the below code snippet def func() { for(i=1; i<=n; i++) { for(j=1; j<=n; j=j+i) { print("hello") } }...
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20votes
8answers
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Why is binary search,which needs sorted data, considered better than linear search?
I have always heard that linear search is a naive approach and binary search is better than it in performance due to better asymptotic complexity. But I never understood why is it better than linear ...
- 3,024
0votes
2answers
363views
fastest way to find number of smaller elements to the right of an array
In Daily Coding Problem, Miller&Wu have the following problem : Given an array of integers, return a new array where each element in the new array is number of smaller elements to the right of ...
- 181
34votes
5answers
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Divide and Conquer algorithms – Why not split in more parts than two?
In divide and conquer algorithms such as quicksort and mergesort, the input is usually (at least in introductory texts) split in two, and the two smaller data sets are then dealt with recursively. It ...
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4votes
1answer
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What is the most suitable data structure for IPv4 addresses with intersecting ranges?
Mostly in all routers and operating systems the Longest Prefix Match algorithm is used for searching the trie of IPv4 addresses. Packet filters like Iptables don't need some special data structure for ...
- 99
5votes
4answers
641views
Processing a 2D matrix - need to speed up my O(n^4) algorithm
I have an n x n matrix which I need to convert into a list sorted by value. Starting with the maximum value cell at (row x1, col y1), I must immediately exclude all cells where (x >= x1, y <= y1)...
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3votes
1answer
417views
Why the names Omega and Theta in Big Omega and Big Theta?
There was a question asking what the "O" stands for in "Big O", the answer to which seems to be "Ordnung von"/"order of". I wonder what's the origin of the ...
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1answer
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Counting primitive operations on recursive functions
I'm reading Algorithm Design and Applications, by Michael T. Goodrich and Roberto Tamassia, published by Wiley. They teach the concept of primitive operations and how to count then in a given ...
