The tag has no wiki summary.

learn more… | top users | synonyms

0
votes
0answers
63 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 ...
-1
votes
0answers
31 views

What are some of the efficient ways to test your algorithms ? [duplicate]

I have just started with competitive programming and must tell you that, I don't have a lot of experience with solving these type of problems. As a result , I started by solving the easiest problems ...
-2
votes
0answers
71 views

How can I improve the following code in terms of faster execution? [migrated]

The problem is described here - Aaah!. My source code for the problem is below. I one of the fast running codes, but not the best. What changes can I make so as to improve the efficiency of the code. ...
0
votes
2answers
84 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
35 views

How do I prove theta(log n)=o(log n)? [migrated]

I'm solving a question from CLRS where we need to prove that (ceil(lg lg n))! is polynomially bounded. Let g(n)=(ceil(lg lg n))! lg(g(n))=lg((ceil(lg lg n))!) =theta(ceil(lg lg n) * lg ...
0
votes
0answers
47 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
80 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
45 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
176 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
votes
0answers
29 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
169 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 ...
0
votes
0answers
144 views

what is the meaning of f(n) = O(g(n))? [duplicate]

I am reading 'Algorithm design manual' book by Steven S. Skiena. I would like to know what is f(n) and g(n)? I am a programmer and wanted to gain more knowledge about algorithms but now I am confused ...
2
votes
1answer
166 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
209 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
142 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 ...
6
votes
3answers
1k 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
118 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
698 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
499 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
191 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
469 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 ...
6
votes
6answers
3k 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
52 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
189 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
801 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
417 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
334 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 ...
20
votes
3answers
2k views

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 ...
2
votes
4answers
333 views

Approach to simplifying an algorithm

For completely random reasons*, I wrote some code that calculates and displays the following expression: P=1*(2+2)(3+3+3)(4+4+4+4)..(n+n...… Which is equivalent to (n!)^2 The version I wrote ...
5
votes
6answers
724 views

How meaningful is the Big-O time complexity of an algorithm?

Programmers often talk about the time complexity of an algorithm, e.g. O(log n) or O(n^2). Time complexity classifications are made as the input size goes to infinity, but ironically infinite input ...
8
votes
1answer
610 views

Possible Damerau-Levenshtein improvement?

I recently implemented the Damerau-Levenshtein distance algorithm from the pseudocode on Wikipedia. I couldn't find any explanation of exactly how it works and the pseudocode uses completely ...
0
votes
2answers
458 views

Does this version of insertion sort have O(n) complexity for best case?

for ( i = 1 ; i <= N ; i++ ) { for ( j = 0 ; j < i ; j++ ) { if ( arr[j] > arr[i] ) { temp = arr[j] ; arr[j] = arr[i] ; for ( k = i ; k > j ; k-- ) ...
5
votes
5answers
668 views

Why interviewers want Optimal Algorithms

In an interview with a software company they asked me some algorithm design questions. Being strong in mathematics I was able to solve it mathematically, but each time when I propose my algorithm ...
3
votes
1answer
713 views

A* Algorithm Completeness Proof

The A* Algorithm is the optimal (provided the heuristic function is underestimated), complete & admissible (provided some conditions). I know the proofs of admissibility & optimality. But how ...
2
votes
1answer
194 views

How to compute amoritized cost for a dynamic array?

I am trying to understand how to do the amortized cost for a dynamic table. Suppose we are using the accounting method. Let A of size m be an array of n elements. When n = m, then we create a new ...
2
votes
1answer
169 views

How much times command executed? Looking for mistake

I have following piece of code: int sum = 0; for (int i = 1; i <= N; i++) for (int j = 1; j <= N; j++) for (int k = 1; k <= N; k = k*2) for (int h = 1; h <= k; ...
0
votes
4answers
3k views

finding the time complexity of the following program

I need to find the time complexity in terms of Big Oh notation for the following program which computes the factorial of a given number: The program goes like this: public int fact(int n){ if (n ...
2
votes
1answer
346 views

Sublinear Extra Space MergeSort

I am reviewing basic algorithms from a book called Algorithms by Robert Sedgewick, and I came across a problem in MergeSort that I am, sad to say, having difficulty solving. The problem is below: ...
0
votes
1answer
174 views

Help with algorithmic complexity in custom merge sort implementation

I've got an implementation of the merge sort in C++ using a custom doubly linked list. I'm coming up with a big O complexity of n^2, based on the merge_sort() > slice operation. But, from what I've ...
1
vote
1answer
377 views

How should I compress a file with multiple bytes that are the same with Huffman coding?

On my great quest for compressing/decompressing files with a Java implementation of Huffman coding (http://en.wikipedia.org/wiki/Huffman_coding) for a school assignment, I am now at the point of ...
2
votes
4answers
721 views

How to discriminate from two nodes with identical frequencies in a Huffman's tree?

Still on my quest to compress/decompress files with a Java implementation of Huffman's coding (http://en.wikipedia.org/wiki/Huffman_coding) for a school assignment. From the Wikipedia page, I quote: ...
1
vote
2answers
188 views

need explanation on amortization in algorithm

I am a learning algorithm analysis and came across a analysis tool for understanding the running time of an algorithm with widely varying performance which is called as amortization. The autor quotes ...
1
vote
1answer
172 views

Does it matter the direction of a Huffman's tree child node?

So, I'm on my quest about creating a Java implementation of Huffman's algorithm for compressing/decompressing files (as you might know, ever since Why create a Huffman tree per character instead of a ...
2
votes
1answer
322 views

Why create a Huffman tree per character instead of a Node?

For a school assignment we're supposed to make a Java implementation of a compressor/decompresser using Huffman's algorithm. I've been reading a bit about it, specially this C++ tutorial: ...
10
votes
7answers
2k views

Big Oh notation does not mention constant value

I am a programmer and have just started reading Algorithms. I am not completely convinced with the notations namely Bog Oh, Big Omega and Big Theta. The reason is by definition of Big Oh, it states ...