Questions tagged [recursive-backtracking]

Recursive backtracking is a general algorithm for finding solutions to computational problems that incrementally builds partial solutions and drops those which are identified as futile *as early as possible*.

Recursive backtracking is a general algorithm for finding solutions to computational problems that incrementally builds partial solutions and drops as early as possible those partial solutions which are identified as futile i.e. such that can not lead to a correct solution.

It essentially involves building nested loops through recursion. Each loop embodies a series of choices. Each inner loop can accept a partial-solution-so-far and try its own choices in a loop, or reject the partial solution it is presented with, through early exit or an equivalent of the continue or break etc. statement.

The control is inverted in that the full solution is achieved in the innermost loop, which can act on it in a particular manner, like printing it to the output / external file, or calling a callback with the solution as an argument.

The backtracking computational structure is embodied in the states of the nested loops, in each of the nested loops' loop variables.

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"Hamiltonian" path using Python

I am trying to implement a recursive search for an arbitrary path (not necessarily a cycle) traversing all graph vertices using Python. Here's my code: def hamilton(G, size, pt, path=[]): if pt not in set(path): path.append(pt) …
Max
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Partitioning an array to maximal number of groups

There is only one rule to follow: each group's sum should be greater or equal to the group on right side of it. My guess is to build a tree with all the options for partitioning exist and then recursive backtracking. For example, the array 14 13 2…
itzikos
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The correct Recursive backtracking algorithm?

My assignment is to find a way to display all possible ways of giving back change for a predetermined value, the values being scanned in from a txt file. This must be accomplished by Recursive Backtracking otherwise my solution will not be given…
Junikin
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What's time complexity of this algorithm for generating all possible valid parentheses?

Generate Parentheses Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. For example, given n = 3, a solution set is: "((()))", "(()())", "(())()", "()(())", "()()()" Personally, I think time…
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how to write iterative algorithm for generate all subsets of a set?

I wrote recursive backtracking algorithm for finding all subsets of a given set. void backtracke(int* a, int k, int n) { if (k == n) { for(int i = 1; i <=k; ++i) { if (a[i] == true) { …
user1886376
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finding all possible longest increasing subsequence using recursion

I tried to find all possible longest increasing subsequence using recursion. When I tried an input array {10,22,9,33,21,50,41,40,60,55}, it worked and the output was: 10 22 33 40 55 / 10 22 33 41 55 / 10 22 33 50 55 / 10 22 33 40 60 / 10 22 33 41 60…
Yurish
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Recursive backtracking to generate mazes

I'm trying to write a maze generator using the recursive backtracking algorithm. I've taken the example code from this article and more or less translated it to javascript. But it doesn't seem to work as all the rows are identical in the generated…
romainberger
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knights tour code with recursion and backtracking

I was recently assigned the knight's tour problem. Here is my try at it: #include #include #include int count = 1; int movej[8] = {1, -1,-2, 2, -2, -1, 1, 2}; int movei[8] = {2, 2, 1, 1, -1, -2, -2, -1}; void…
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How Backtracking works in programming languages?

I am using recursion with backtracking, i have used multiple recursion call My code snippet : - func test(currentIndex: Int, op: inout [Int]) { if currentIndex > 1 { print("exit here**********************") return } …
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Is it possible for backtracking N-queens to produce O(n^2) time complexity

The backtracking approach for n-queens is clearly O(n!). However I am looking at these links here: https://algodaily.com/challenges/classical-n-queen-problem https://www.geeksforgeeks.org/n-queen-problem-backtracking-3/ They give O(n^2) time…
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Recursive backtracking algorithm for the 'coin change problem'

I'm trying to solve the "Coin Change Problem" by implementing a recursive backtracking algorithm which will analyze all possible outcomes and show the optimal combination of coins. Unfortunately, I have no idea how I can compare the different…
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Recursion backtracking interview question

I was asked this interview question on recursion & backtracking the other day and have not found a feasible solution, here is the question: Given a grid and a word, write a function that returns the location of the word in the grid as a list of…
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Partition set with constraints (backtracking with Python)

I have a set of N items that I want to split in K subsets of size n1, n2, ..., nk (with n1 + n2 + ... + nk = N) I also have constraints on which item can belong to which subset. For my problem, at least one solution always exist. I'm looking to…
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Can't get backtrack to work on recursive javascript sudoku sovler

I'm racking my brain but I can't see where I've gone wrong, from the console log it appears it's an issue when it comes to backtracking not working correctly, I think it has something to do with how I'm working with position object, any help would…
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Complexity of backtracking algorithm with and without memorization

The problem is as follow: Our input is an array of 14 numbers and our output is whether this is a winning hand. For a hand to be a winning hand it must be possible to divide its numbers into groups with the following rules: Each group of 3 must be…
user1692261
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