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Questions tagged [space-complexity]

The space complexity of an algorithm quantifies the amount of memory taken by an algorithm to run as a function of the size of the input to the problem. The space complexity of an algorithm is commonly expressed using big O notation, which suppresses multiplicative constants and lower order terms.

The space complexity of a program (for a given input) is the number of elementary objects that this program needs to store during its execution. This number is computed with respect to the size n of the input data.
Formally, for an algorithm T and an input x, DSPACE(T, x) denotes the number of cells used during the (deterministic) computation T(x). We will note DSPACE(T) = O(f (n)) if DSPACE(T, x) = O(f (n)) with n = |x | (length of x).

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Big O complexities of algorithms - LZW and Huffman

What are the space and time complexities, in Big O notation, for the Lempel-Ziv-Welch and Huffman compression algorithms? Google is failing me. Thanks, Francisco
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What is the worst case scenario for an unordered_map?

I have found many posts about the complexity of map and unordered_map. It is said that unordered_map has worst case complexity of O(N). For my purpose I will have input as sorted values like 1 2 5 6 9 11 12... I need to insert or find and delete a…
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C++ Time and Space Complexity of string class erase member function

I wanted to know if someone knew the implementation of the C++ string::erase function and it's complexity. I know the C++ string is an object of characters. I'm assuming it doesn't allocate and create a new object of characters and then copy over…
B Stoops
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Is it possible to implement quicksort with O(1) space complexity?

From what I understood in Wikipedia's explanation of quicksort's space complexity, quicksort's space complexity comes from its recursive nature. I'm curious as to whether it's possible to implement quicksort non-recursively and, in doing so,…
Daniel
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Python list.clear() time and space complexity?

I am writing a blogpost on Python list.clear() method where I also want to mention about the time and space complexity of the underlying algorithm. I expected the time complexity to be O(N), iterate over the elements and free the memory? But, I…
Pankaj Mishra
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Do variables declared in loop make space complexity O(N)?

Would variables declared inside of a for loop that loops N times make the space complexity O(N) even though those variables fall out of scope each time the loop repeats? for(var i = 0; i < N; i++){ var num = i + 5; }
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Space Complexity of an array?

I have an array of size N, and N is <=200. What would be the space complexity here. O(1) or (N) - considering the constraint N.
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HashMap Space Complexity

Here's a sample solution for "Populating Next Right Pointers in Each Node" puzzle: Populate each next pointer to point to its next right node. If there is no next right node, the next pointer should be set to NULL. public void connect(Node root)…
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Space complexity of head.reverse vs. last

In many systems, head.reverse requires space proportional to the size of the list, whereas last requires constant space. Are there systems to perform such a transformation? Similarly for reverse.take n.reverse? Edit: I would like to extend my…
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Space complexity of recursive algorithm

I was asked at an interview, the efficient way to solve a problem checking for pallindrome. Now i can do two things: starting from i = 0 to i = n/2 and comparing ith and n-ith character to be equal. I can use recursion to check if first and last…
dharam
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Can we compute this in less than O(n*n) ...( nlogn or n)

This is a question asked to me by a very very famous MNC. The question is as follows ... Input an 2D N*N array of 0's and 1's. If A(i,j) = 1, then all the values corresponding to the ith row and the jth column are going to be 1. If there is a 1…
Flash
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Is this function (for loop) space complexity O(1) or O(n)?

public void check_10() { for (string i : list) { Integer a = hashtable.get(i); if (a > 10) { hashtable.remove(i); } } } Would this be O(1) or O(n)? I'm guessing O(n), but isn't it reusing the spot of…
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Meaning of the terms O(1) space and without using extra space

This is slightly confusing to me. What should be my approach of solving a given problem when the constraint is as follows: 1) Without using extra space: For e.g.: If I want to sort a given array, I have few ways of doing it. Bubble sort, which…
dharam
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Tutorial on space complexity of algorithms

Possible Duplicate: Plain English explanation of Big O I have always struggled to calculate the Big-O time and space complexity of the algorithms I write. Can anybody please point to a good resource for studying more about space complexity of…
stressed_geek
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What is O(1) space complexity in term of Javascript code with example

For an example I have below mentioned input and output for function reverseWords() It's a simple example but this will help me understand. How I will write a function which is In O(1) space for below request ? // var input = ['H', 'e', 'l', 'l',…
Javascript Coder
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