Combinatorics is a branch of mathematics concerning the study of finite or countable discrete structures.

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Generating all possible permutations of the string

This generates all possible permutations of the string. I am also unable to understand the time complexity of this problem. Can someone please explain the complexity to me? ...
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1answer
44 views

Python small brute-forcer

I have 20+ key set. Keyset is like: Key[0] = { "PossibleKey0", "PossibleKey0Another", "AnotherPossibleKey0" } Key[1] = { .... There is an encryption which needs ...
13
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1answer
92 views

Advanced and Detailed Minesweeper Probabilities

In an earlier question, I showed my code for calculating the mine probability for each and every field in a Minesweeper board. But it doesn't stop there. In that very same Minesweeper Analyze project, ...
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2answers
120 views

A Specific Combination

This code is going to be included in my Minesweeper Probabilities project. (so far it only exists on the develop-branch) The purpose is to return a specific combination, let's say for example that ...
2
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3answers
80 views

Finding combinations of 3 numbers

What this code tries to do is find possible combinations of three numbers. For example, let's say I have the following numbers: 1, 2, 3, 4, 5, 6, 7 Some ...
5
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2answers
71 views

'Countdown' Numbers round - combine numbers arithmetically to reach a target

Countdown is a British gameshow where contestants compete in word and number challenges. During the numbers round, six numbers are chosen semi-randomly and the task is to combine them using addition, ...
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1answer
69 views

Print all permutations of a given string in Java

I want to print all permutations of a given string in Java. To do this I create one auxiliary array boolean used[] to check if I have used some character or not. ...
3
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1answer
90 views

Print all possible combinations of size r, from an array of size n

This is my working solution for the following problem: given an array of integers of size n, print all possible combinations of size r. Before I proceed to the solution, I have the following ...
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1answer
52 views

Combinations with replacement

I am still new to Scala and wrote a small snippet to find all the combinations with replacement of a sequence (e.g. cwr(ab, 3) should give aaa, aab, abb, bbb). The slow way would be to generate all ...
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1answer
130 views

Recursive function that generates the permutations of a string

I am looking for a review of my recursive function that generates the permutations of a string. Are there better ways to do this? ...
6
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2answers
86 views

How can I optimize this combination method?

I have this method that is working perfectly fine, but it's very slow, and sometimes I have to wait 15 minutes to get a good result, which is ok. I'm wondering if I can make it faster. Basically I'm ...
4
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3answers
119 views

Another permutator

This is a solution to this problem. The problem statement: write a program to display all possible permutations of a given input string--if the string contains duplicate characters, you may have ...
6
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1answer
53 views

Generating Cartesian product of strings in R

Sometimes I need to create character vectors like this one: ...
5
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2answers
101 views

Binomial coefficient

I wrote a C++ function to calculate the binomial coefficient, trying to avoid overflows as much as possible. ...
5
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2answers
72 views

Possible combinations following a rule

The problem is the following: We have a number of months to buy a number of supplies. The sooner we finish buying them, the better, but we don't know how much we can buy per month and would like to ...
4
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1answer
109 views

Seeking improved Objective-C permutation algorithm

This algorithm seeks to find all of the possible permutations of a word: ...
12
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3answers
373 views

Generate all possible combinations of letters in a word

This is a JavaScript function that returns ALL the possible combinations of whatever word the user enters. I am looking to clean this code up a bit...any and all suggestions are welcome! ...
4
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1answer
99 views

Permutations program in Python

This code asks for letters and a number of letters per word and generates all possible permutations. Then compares those permutations with an English dictionary and creates a list with all the words ...
3
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1answer
86 views

Finding the 'Minimum' AND of all the possible subsets of a set

The subset size should be greater than or equal to 2. How can I speed up this code? ...
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1answer
101 views

Verifying boardgame mathematics with MATLAB

I recently bought this math-based boardgame for my little cousins, and am now trying to verify its design with some MATLAB code. The relevant parts of the game are: A board with numbers from 1 to ...
21
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3answers
457 views

Analyzing Minesweeper Probabilities

Calculating probabilities in Minesweeper might sound like an easy task, but I've seen so many probability calculators that's either incorrect, horribly slow, or with ugly code (or all of them) so I ...
6
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5answers
563 views

Improving efficiency of Project Euler 185 (16-place Mastermind)

This a solution for Project Euler Problem 185. It works fine for the example but slow for the problem statement. How can I improve its speed and efficiency? ...
3
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2answers
438 views

Calculate all possible combinations of an array of arrays or strings

I'm using code adapted from this Stack Overflow question to calculate all possible combinations from an array, which may contains strings. For example: ...
13
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7answers
2k views

Is my solution to return kth row of the Pascal's triangle suitable for a job interview?

Question: Given an index \$k\$, return the \$k\$th row of the Pascal's triangle. For example, given \$k = 3\$, return \$[1,3,3,1]\$. Bonus points for using \$O(k)\$ space. Can it be ...
7
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3answers
544 views

Get distinct combinations of numbers

The below code returns all distinct combinations based on the logic that 1,2,3 = 3,2,1 = 2,3,1, so it only returns 1 instance of that set of numbers. ...
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1answer
46 views

Find triangles from line

I have some lines that form triangles. I'd like to challenge the fastest way to find all triangles. In particular the code should take an ArrayList of Line2D object and return an ArrayList of ...
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2answers
87 views

Simplified Bin Packing using JavaScript

This code determines the maximum number of boxes (one size) that can fit into the back of a truck, checking all possible orientations to ensure maximum Bin Packing excitement. This is (hopefully) the ...
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1answer
142 views

Given a shape, return all triangles that can be formed

Given a shape, get all triangles that can be possible by connecting the points. Example: given 3 points, only 1 triangle is possible, but given a pentagon, 10 are possible. Also the ...
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4answers
132 views

Better way to achieve looped output result

I have 4 variables - say A, B, C and D Each variable can have 4 values - say 1, 2, 3 and 4 I need to generate all possible combinations of values Example of Expected Output: ...
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3answers
70 views

Curious fractions in functional Ruby

Problem 33 in Project Euler asks: The fraction 49/98 is a curious fraction, as an inexperienced mathematician in attempting to simplify it may incorrectly believe that 49/98 = 4/8, which is ...
7
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1answer
101 views

Speeding up subset sum implementation

Important fact: the number of the input is greater than 1. How do I use this fact to speed up this solution? ...
7
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3answers
221 views

Optimizing unique partitions of integers

I am working on a project involving the unique partitioning of integers. I.e. I am looking to have all of the partitions of n = x1 + x2 + x3 + ... + xk, where xi = xj implies i = j. For example, if I ...
7
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1answer
71 views

Compute stats on two class vectors

Below is a full working code example of code which is used to compute stats on two class vectors (partitions). There are two functions: pairwise_indication and ...
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2answers
165 views

Printing permutations of a given string

I want some feedback on the program I developed in C for printing the permutations of a given string. ...
0
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1answer
111 views

Finding the number of permutations of an integer array with equaling difference (not in order)

The array size is <= 16. The difference is defined as: diff[i] = array[i+1] - array[i]; I need to find the number of permutations of the original array, which ...
4
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0answers
295 views

Nonogram puzzle solution space

I've written some code to brute-force enumerate the solution space of nonogram puzzles up to a certain size. It does a good job up to the first ~4 billion puzzles, but I run out of disk space to store ...
7
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2answers
137 views

Generate permutations with symbols

Goal: Create a combination of emails based from inputted first name, last name, middle name, and a domain. Add in common separators. Then I'll check which one is correct with the rapportive API. This ...
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3answers
361 views

Prints out all ways to multiply smaller integers that equal the original number

Write a program in Java that takes a positive integer and prints out all ways to multiply smaller integers that equal the original number, without repeating sets of factors. In other words, if ...
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0answers
62 views

Find the combinations, given three datacenters with x number of machines [closed]

I am working on a project in which I have three datacenter (as of now) and each datacenter will have some machines. So I am storing the input in a ...
5
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1answer
115 views

Project Euler #15 in haskell

I've solved Project Euler #15 in Haskell, but I feel like there might be a better way to express my solution that I'm not seeing. I start out defining my types: ...
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2answers
773 views

Permutation of a string eliminating duplicates

This code lists the permutations of the string, and eliminates duplicates if any. I'm looking for code review, best practices, optimizations etc. Also verifying complexity: O(n! * n) as time ...
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3answers
5k views

Calculate all possible combinations of given characters

I was asked in my textbook Lectures on Discrete Mathematics for Computer Science to construct a program that would take an alphabet ({a,b,c} or any combination of ...
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2answers
187 views

Print routes on the stairway when only 1 or 2 steps are possible

Given a staircase with N steps, you can go up with 1 or 2 steps each time. Output all possible ways you go from bottom to top. I'm looking for code review, best practices, optimizations etc. ...
3
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1answer
361 views

Find all permutations of a string in C++

I need a review of the following code for finding all permutations of a string in C++: ...
10
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3answers
3k views

Brute Force Algorithm in C

This is a simple brute force algorithm I have in C. All the program does it print out every possible combination of the given alphabet for the given length. I ...
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1answer
461 views

Fastest way for working with itertools.combinations

I need to speed up the function below: ...
2
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1answer
51 views

Produce product of lists

I want to combine elements in different lists. For example, here are 3 lists. list_a : [ 1,2,3 ] list_b : [ 4,5,6 ] list_c : [ 7,8 ] Selecting elements from ...
3
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2answers
118 views

Determine if a word can be constructed from list of subsets - follow-up

I have reworked my code as suggested from my previous question: Determine if a word can be constructed from list of subsets. Please instruct me on the complexity along with a review feedback, as ...
2
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2answers
127 views

Determine if a word can be constructed from list of subsets [closed]

The question is explained well by examples in the comments below. Also I request verifying complexity: O( n * n!), where n is the number of words in the subsets. Review my code for optimizations, ...
4
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2answers
146 views

Integer Partition using an iterator

I tried implementing Integer Partition (enumerating all possible sets of whole numbers whose sum is a given integer). Looking at @rolfl's answer, I reasoned that with a stack data structure, we ...