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0
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0answers
26 views

Check distance between all elements in a list of numbers in O(n*lg(n))

I have an exercise for my algorithms and data structures class, where I basically have to implement a divide and conquer algorithm or function called check_distance to determine whether all numbers in ...
1
vote
1answer
80 views

More efficient alternative that checks if a list can be made a palindrome

I asked this question on Stackoverflow, but they told me this is the best place to ask. For my algorithms and data structures class, I have to write an algorithm that is more efficient in the worst ...
5
votes
1answer
102 views

Compute Adjacent Pair

I was asked the following question as part of an interview: Integer V lies strictly between integers U and W if U < V < W or if U > V > W. A non-empty zero-indexed array A consisting of ...
1
vote
2answers
108 views

Estimating run time of algorithm

For instance if i have an algorithm that is O(n2) and it will run for 10 seconds for a problem size of 1000. Now if i were to double the problem size to 2000 i want to know the approximate run time in ...
1
vote
2answers
93 views

Algorithm Space and Time Complexity with Consideration for I/O (eg cache)

Is there an expression of performance for an algorithm or data structure that attempts to consider cache and other hardware concerns? Context: in my class we're looking at binary trees and it seems ...
1
vote
1answer
57 views

Connected components of undirected graph

Suppose I have an undirected graph G with vertices v1...vn and edges. Right now it is in adjacency list representation. For every time moment I have as input some subset of vertices that are "active" ...
-1
votes
1answer
83 views

worst case comparisons for special case insertion sort [closed]

Consider an Insertion Sort with a Sentinel on n values, where every value occurs exactly twice in the input (so n must be even). So the best case input for comparisons is when the elements are ...
0
votes
2answers
65 views

Time complexity analysis for recurrence relation

I was asked to figure out the time complexity analysis for the following recurrence relation T(n) = 4*T(n-1) + c. Basically, I did a replacement.. T(n-1) = 4 * T(n-2) + c and so on.. T(n) = 4^k T(1) ...
-2
votes
1answer
66 views

Time complexity for a recurrence relation using Divide and Conquer Master Theorem [closed]

For the recurrence relation : T(n) = 16T(n/4) + n! I have found that the order is Θ(n!). But I don't understand how it can be deduced using Master Theorem.
0
votes
2answers
200 views

Big-O notation for other cases

I was just reading answers to a question Plain English explanation of Big O From that i came to know that Big-O notation is just an "upper bound" of the complexity of an algorithm? But can we apply ...
1
vote
2answers
146 views

Lower and Upper bound of an algorithm

I am learning about analysis of algorithms. I came across the term "upper bound" and "lower bound" in "worst-case" running time of an algorithm. Are they applicable to only the "worst case" or can ...
0
votes
1answer
339 views

Which weak algorithmic strategies I have that lead me to failing coding this simple algorithm? [closed]

I am a graduate student in computer science who graduated recently from a famous university. I applied to my first software engineering job and I failed the technical interview by failing to answer ...
0
votes
1answer
190 views

Shortest path to visit all nodes [duplicate]

I am given a set of tourist attractions(nodes identified by x, y) and i need to find the shortest path to visit them. The way i thought of it, is i will ignore if there are streets available and ...
4
votes
3answers
126 views

Algorithm Analysis: In practice, do coefficients of higher order terms matter?

Consider an^2 + bn + c. I understand that for large n, bn and c become insignificant. I also understand that for large n, the differences between 2n^2 and n^2 are pretty insignificant compared to the ...
4
votes
2answers
287 views

Loop runtime question

I had an exam today and I feel that I did pretty well, except I could not for the life of me figure out what appears to be an unbelievably simple question. We were asked to give theta notation run ...
0
votes
2answers
104 views

What's the professional name for the software planning diagrams, those with ellipses and rhombuses?

What's the official name for a diagram like this one, used to structure a conditional plan. The shapes of the objects are by convention ellipse for an action, rhombus for a question, rectangle for a ...
0
votes
0answers
18 views

A heuristic approach to Clique problem over undirected Graph

I'm trying to get all complete subgraph given a graph G. Needless to say it is an NP-problem complete: Clique_problem. I understand getting the full set is not possible in real time(since it'll take ...
1
vote
1answer
114 views

Check word density within a document

Here is the situation: I have a Document(d) and a set of keywords (Set<String> keywords). I like to check the density of each words from set keywords with d. I have few solution but not really ...
16
votes
5answers
4k views

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; ...
2
votes
3answers
84 views

recalculation model for GUIs

I often come across this problem. Say to have a form with some controls: A B C = A + B D E = C * 2 ONLY IF D==TRUE F G = A - F The user fills A, then B. The system calculates C. The user fills D ...
0
votes
2answers
290 views

How are the tiles in WORDAMENT organized?

I'm trying to create a word game, just like WORDAMENT, in my spare time. In order to present a new round, I need to create a board with 16 letters organized in a 4*4 grid. Currently, I'm generating ...
1
vote
2answers
183 views

How to measure algorithm accuracy?

I have a few optimization algorithms (for finding function minimum) and I'd like to check how good they are. Suppose I build test cases and compare the actual results to theoretical ones. What ...
0
votes
0answers
135 views

Approach for packing 2D shapes while minimizing total enclosing area

Not sure on my tags for this question, but in short .... I need to solve a problem of packing industrial parts into crates while minimizing total containing area. These parts are motors, or pumps, ...
0
votes
2answers
121 views

How to avoid or minimise use of check/conditional statement in my scenario?

I have scenario, where I got stream and I need to check for some value. If I got any new value I have to store it in any of data structure. It seems very easy, I can place conditional statement ...
2
votes
1answer
189 views

Asymptotic running time of for-loops

I have this question which I need answered: What is the asymptotic running time for the following piece of code? if (N < 1000) for (int i = 0; i < N; i++) for (int j = 0; j < N; ...
1
vote
2answers
326 views

How to approach program design with respect to data strucutres and algorimths - is there an equivelant of the OO design process for d.s.'s + algs? [closed]

My applogies for probably the worst written body of text I have produced in my life and many thanks to those willing to plough through it all. I was (and still am) not able to clearly express what I ...
1
vote
1answer
91 views

Confusion in understanding the theorem on Amortization

I was reading a book on Algorithm Analysis by Micheal T Goodrich. I came across amortization technique and I got struck in understanding the proof of theorem. I am putting the theorem and the proof ...
0
votes
0answers
142 views

GSP Algorithm explanation

I've been trying to implement the GSC algorithm in C++, however I need help with clarifying the definition: http://en.wikipedia.org/wiki/GSP_Algorithm GSP Algorithm makes multiple database ...
0
votes
2answers
448 views

calculate complexity of LinkedHashSet

I have an ArrayList<LinkedHashSet<String>> setOfStrings for example this arraylist internally is composed like: positionX[hello,car,three,hotel,beach] positionY[.....] ... I want to ...
0
votes
0answers
139 views

Would Someone explain me this Random Walk Algorithm for Onion Routing?

The Algorithm below is written in pseudocode and for simplicity the storage of the actual route in the Data structure is not included. LengthFromSrc = 0; LengthFromDest = 0; TotalNumberHops = ...
0
votes
0answers
98 views

Algorithm / working approach to get a random list of data

I am working on a android schedule app but that isn't matter , the problem is a algorithm / methodology so you are welcome to just write the pusedo code to answer. The data is like this Place ...
2
votes
1answer
46 views

What is the order analysis of the following (using a list of primes)

I have the following program: Iterate x from 1 to N. Check to see if x is prime. If it is, add it to a list of primes. The way I check to see if it is prime is iterating through the current list ...
1
vote
2answers
312 views

Given two sorted array in ascending order with same length N, calculate the Kth min a[i]+b[j]. Time complexity O(N)

Given two sorted array in ascending order with same length N, calculate the Kth min a[i]+b[j]. Time complexity O(N). Another variant of the question goes like this: given a matrix with sorted rows, ...
0
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0answers
34 views

Readers Writers algorithm help - starvation and no starvation

I found this link, as an explanation of r/w problem - http://pages.cs.wisc.edu/~bart/537/lecturenotes/s7.html But, I'm having problems realizing is there any starvation present here and why? Also, if ...
0
votes
1answer
419 views

How to develop an algorithm for brute-forcing / backtracking?

As a beginner programmer, I don't know how to conceptually think about brute-forcing. My mind can't really fathom how to write code that will try every possibility. I have a problem that I want to ...
3
votes
1answer
477 views

How this Fibonacci exponentiation by squaring algorithm works?

This is one of the best algorithms to calculate the nth Fibonacci sequence. it needs O(log(n)) time to do its job, so it's so efficient. I found it somewhere but don't know how it works! Can anyone ...
1
vote
4answers
315 views

How to trace logical errors in algorithms [closed]

I am beginner in algorithms. Last year I participated in Google Code Jam. One of the major issues I faced during the competition was my code was working fine on my test cases, but when I submitted on ...
3
votes
1answer
201 views

Sentence Tree v/s Words List

I was recently tasked with building a Name Entity Recognizer as part of a project. The objective was to parse a given sentence and come up with all the possible combinations of the entities. One ...
7
votes
3answers
3k views

Why Big Data Needs To Be Functional?

I started working on a new project lately related to Big Data for my internship. My managers recommended to start learning functional programming (They highly recommended Scala). I had a humbled ...
1
vote
1answer
140 views

How to calculate the worst-case runtime of this search-algorithm

I've written a special indexOf function for a list of unsorted unique values. I can search for one or multiple (unsorted) values, passed as array/list, and the function will return me an array/list ...
-4
votes
1answer
1k views

What is the big-O cpu time of Euclid's Algorithm of “Greatest common divisor of two numbers”

Looking at Euclid's algorithm for the "Greatest common divisor of two numbers", I'm trying to divine the big-O cpu time for numbers K, and N. Can anybody help? This is the algorithm as I understand ...
5
votes
2answers
959 views

difference between accounting and potential methods in Amortized Analysis

I was going through the Introduction to Algorithms by Cormen et al.In the chapter titled Amortized Analysis,the difference between accounting and potential methods is given like this The ...
5
votes
1answer
230 views

Bin sorting problem - Please help categorize

I have a problem I am developing a solution for and currently I solve it with a brute force solution that checks all possibilities. It works for small numbers of bins but I'd like to work with a ...
13
votes
2answers
506 views

Trying to understand the 2N lnN compares for quicksort

I was going through the analysis of quicksort in Sedgewick's Algorithms book. He creates the following recurrence relation for number of compares in quicksort while sorting an array of N distinct ...
9
votes
7answers
6k views

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 ...
0
votes
1answer
62 views

clarification about amortized analysis

I was going through an article here In the section named Aggregate Method ,the author says Then summing over the entire sequence, all the 1's sum to O(n), and all the di also sum to O(n). That ...
2
votes
1answer
205 views

Algorithm in undirected BFS graph

I'm trying to put together an algorithm that will display the node degree for every node in a breadth first tree graph (assume BFS was called). Assume it's an undirected graph. I'm not sure how to ...
1
vote
1answer
1k views

Matrix Pattern Recognition Algorithm for a 2D space

I have a picture that I elaborate with my program to obtain a list of coordinates. There is a matrix represented in the image. In an ideal test I would get only the sixteen central points of each ...
5
votes
4answers
734 views

Find the peak of each islands in sparse matrix

I have a sparse matrix that contains several islands of unknown size. I would like to find the highest peak of each islands. Consider this matrix as an example: 0 0 1 0 0 0 0 0 0 1 2 1 0 0 0 0 0 3 2 ...
0
votes
1answer
457 views

Priority queue for Kruskal's algorithm with running time O(E lg V)

I'm reviewing my notes on Kruskal's algorithm and have a question about getting the runtime down to O(E lg V). By using a PQ with edges and a boolean array of which vertices we have added to our tree ...