In C, you can use the built in qsort command: see: http://www.cplusplus.com/reference/clibrary/cstdlib/qsort/ To answer the second part of your question: an optimal (comparison based) sorting algorithm is one that runs with O(n log(n)) comparisons. There are several that have this property (including quick sort, merge sort, heap sort, etc.), but which one to use depends on your use … Read more
What you have coded in your example is very similar to a depth first search. So, that’s one answer. A depth first search algorithm without any special characteristics ( like re-convergent paths that can be optimized out ), should be n^n. This is actually not a contrived example. Chess programs operate on the same algorithm. … Read more
This problem can be solved with a recursive combinations of all possible sums filtering out those that reach the target. Here is the algorithm in Python: This type of algorithms are very well explained in the following Stanford’s Abstract Programming lecture – this video is very recommendable to understand how recursion works to generate permutations of solutions. … Read more
It means that the thing in question (usually running time) scales in a manner that is consistent with the logarithm of its input size. Big-O notation doesn’t mean an exact equation, but rather a bound. For instance, the output of the following functions is all O(n): Because as you increase x, their outputs all increase linearly – if there’s … Read more
Do you know, f(n) = O(g(n)) implies f(n) <= constant* g(n), right? In other words, it means, when you plot the graph of f(n) and g(n) then after some value of, g(n) will always be more than f(n). Here g(n) is N^3 and remaining comes in f(n). Now, N^3 is always >= options a, b, c. hence answer id D 🙂 Edit: Following statements are true, n=O(n) n=O(n^2) n=O(n^3) But only n = O(n) is tight upper bound and that is what … Read more
Bucket sort and radix sort are close cousins; bucket sort goes from MSD to LSD, while radix sort can go in both “directions” (LSD or MSD). How do both algorithms work, and in particular how do they differ?
While trying to understand the difference between Theta and O notation I came across the following statement : But I do not understand this. The book explains it mathematically, but it’s too complex and gets really boring to read when I am really not understanding. Can anyone explain the difference between the two using simple, … Read more
If you REALLY want to brute force it, try this, but it will take you a ridiculous amount of time: On a smaller example, where list = ‘ab’ and we only go up to 5, this prints the following:
You can use the Median of Medians algorithm to find median of an unsorted array in linear time.
The basics first: The Mean Shift segmentation is a local homogenization technique that is very useful for damping shading or tonality differences in localized objects. An example is better than many words: Action:replaces each pixel with the mean of the pixels in a range-r neighborhood and whose value is within a distance d. The Mean … Read more