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3
votes
1answer
278 views

Sentence Tree vs. 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 ...
2
votes
1answer
81 views

Optimizing the exponential smoothing of a big array

I have a large set of values (let's say 1M entries) where I need to apply an exponential smoothing algorithm, but only incrementing one value at a time (all others decay to zero). The trivial ...
5
votes
8answers
2k 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 ...
0
votes
1answer
35 views

Search list items from other list, better way?

Today I have to search items of list from another list individually. I am just thinking about some better approach. Below is scenario described. Lets say I have two arrays, arr1 having 100 elements ...
1
vote
3answers
388 views

Big O notation of randomness

I was thinking about inefficient algorithms based on randomness and wondered how to categorise them. For instance. Say you wanted to generate all the numbers from 1 to N in a random order but only ...
2
votes
4answers
485 views

What is Big-O notation for purely functional languages?

Is it still relevant? Instead of var result = new List<int>(); for (var i = 0; i < prev.Count; ++i) { result.Add(prev[i] * 2); } where the result.Add, prev[i], and * 2 instructions ...
0
votes
3answers
269 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 ...
-2
votes
1answer
153 views

How to find complexity of T(n) = 8T(n/2)+n^2.93(log n)^93?

I believe we have to use a variant of master theorem...can someone suggest me how to find complexity of such equation which doesn't directly fit into Masters theorem.
5
votes
3answers
837 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 ...
-2
votes
1answer
84 views

Unable to Solve Dynamic Programming

I had an assignment on dynamic programming due last night, but I had to turn it in unfinished because i could not understand how to solve the last problem: The state wants to monitor traffic on a ...
11
votes
2answers
336 views

Time complexity of 2^sqrt(n)

I am solving an algorithm question and my analysis is that it would run on O(2^sqrt(n)). How big is that? Does it equate to O(2^n)? Is it still non-polynomial time?
30
votes
5answers
5k 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 ...
5
votes
2answers
306 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 ...
1
vote
2answers
770 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 ...
1
vote
3answers
221 views

Data structure for sorting by multiple attributes

I have a list of integer pairs. The value of this list is the sum of the maximum values of each pair. For (0, 5) (20, 5) (6, 8) the value would be 5 + 20 + 8 = 33 Given a list like ...
3
votes
1answer
94 views

Are these graph coloring algorithms equivalent?

Suppose you want to color the vertices of a graph in a greedy fashion, given a predetermined order of these vertices. The goal is to avoid giving two adjacent (linked by an edge) vertices the same ...
1
vote
0answers
88 views

Belman-Ford 2d array variation problem

I've got a problem with applying a Bellman-Ford algorithm to 2D Array (not to graph) Input array has m x n dimensions: s[1,1] s[1,2] ... s[1,n] -> Exit s[2,1] s[2,2] ... ...
3
votes
1answer
2k 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
75 views

Running time of the specified Bubble Sort Algorithm

I have been working on a few algorithm questions the last few days, and one bubble sort problem in particular has been giving me headaches. for (k=1; k <= A.length - 1; k++) { //Line 1 ...
1
vote
3answers
257 views

What's the big-O complexity of this recursive algorithm?

I am following a course of Algorithms and Data Structures. Today, my professor said the complexity of the following algorithm is 2^n. I waited till the lesson was over, approached him and told him ...
3
votes
2answers
220 views

Big O Nested For Loop Breakdown

I understand how to get a general picture of the big O of a nested loop, but what would be the operations for each loop in a nested for loop? If we have: for(int i=0; i<n; i++) { for(int ...
5
votes
3answers
771 views

Is O(log n) + O(log n) = O(n)? [duplicate]

We know that binary search takes O(log n) in Big O notation but if we need to run twice an algorithm of O(log n), would it be the same as O(n) in time complexity? For example, if I have a method to ...
1
vote
2answers
684 views

Is the time complexity of a while loop with three pointers different than 3 nested for loops?

This program (written in ruby) finds the largest 3 numbers in an array (without sorting the array). It has a while loop with three pointers. My fist instinct, since there is only one loop is to say ...
0
votes
2answers
140 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) ...
19
votes
4answers
3k views

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
0
votes
4answers
11k views

Finding the time complexity of the following program that uses recursion

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 ...
1
vote
2answers
226 views

What is the algorithmic time complexity of this program?

I wrote a simple program in java to create and maintain Dynamic Arrays: public class DynamicArrays { private Integer[] input = new Integer[1]; private Integer length = 0; private Integer ...
0
votes
3answers
361 views

Best algorithm to determine whether two arrays can be the same in a circular queue

I'm trying to figure out an efficient way to determine whether two distinct arrays of the same size can be shifted to form the same circular queue. For example: Array1 = ['A','B','C','D'] Array2 = ...
1
vote
3answers
363 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 ...
-3
votes
4answers
209 views

Time complexity of this loop [duplicate]

Is the time complexity for this loop O(n) or O(log n)? for(i=0;i<n/2;i++){} I am thinking, the time is proportional with the input size.
0
votes
2answers
598 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 ...
2
votes
3answers
253 views

Close to knapsack problem?

I think that I am trying to solve a problem somewhat similar to a knapsack problem. I am not sure though. Please see the input given below and my solution. There are three types of items and 4 ...
5
votes
1answer
1k views

Compute Adjacent Pair

I was given the following problem: 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 N integers is given. A ...
1
vote
1answer
2k views

Calculate Big-O for nested for loops

I found this nested loop to calculate the Big-O notation. for(i=0;i<n;i++) for(j=0;j<i*i;j++) for(k=0;k<j;k++) I got the time complexity for the algorithm with this polynomial ...
1
vote
2answers
185 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
113 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 ...
2
votes
2answers
430 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
1answer
215 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
762 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 ...
12
votes
7answers
13k 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 ...
-2
votes
1answer
184 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.
1
vote
2answers
2k 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
442 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
171 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 ...
1
vote
2answers
1k 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 ...
6
votes
2answers
1k views

Space complexity of Iterative Deepening DFS

We read on Wikipedia > Iterative deepening depth-first search that The space complexity of IDDFS is O(bd), where b is the branching factor and d is the depth of shallowest goal. Wikipedia also ...
1
vote
2answers
144 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 ...
17
votes
5answers
8k 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; ...
1
vote
1answer
274 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 ...
2
votes
3answers
98 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 ...