scholarly journals Exact Method for Generating Strategy-Solvable Sudoku Clues

Algorithms ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 171
Author(s):  
Kohei Nishikawa ◽  
Takahisa Toda
Keyword(s):  
Time Limit ◽  
Exact Method ◽  
Limit Set ◽  
Brute Force ◽  
Regular Pattern ◽  
Brute Force Search ◽  
Running Time ◽  
Minimum Number ◽  
Rigorous Framework

A Sudoku puzzle often has a regular pattern in the arrangement of initial digits and it is typically made solvable with known solving techniques called strategies. In this paper, we consider the problem of generating such Sudoku instances. We introduce a rigorous framework to discuss solvability for Sudoku instances with respect to strategies. This allows us to handle not only known strategies but also general strategies under a few reasonable assumptions. We propose an exact method for determining Sudoku clues for a given set of clue positions that is solvable with a given set of strategies. This is the first exact method except for a trivial brute-force search. Besides the clue generation, we present an application of our method to the problem of determining the minimum number of strategy-solvable Sudoku clues. We conduct experiments to evaluate our method, varying the position and the number of clues at random. Our method terminates within 1 min for many grids. However, as the number of clues gets closer to 20, the running time rapidly increases and exceeds the time limit set to 600 s. We also evaluate our method for several instances with 17 clue positions taken from known minimum Sudokus to see the efficiency for deciding unsolvability.

scholarly journals Perbandingan Algoritma Boyer-Moore dan Brute Force pada Pencarian Kamus Besar Bahasa Indonesia Berbasis Android

2021 ◽  
Vol 1 (2) ◽  
pp. 54-60
Author(s):  
Candra Irawan ◽  
Mudafiq Riyan Pratama
Keyword(s):  
String Matching ◽  
Search Process ◽  
Brute Force ◽  
Text Search ◽  
Matching Algorithm ◽  
Running Time ◽  
The Right ◽  
Bahasa Indonesia ◽  
Testing Criteria

String matching is an algorithm for matching a text to another text or also known as a text search. There are several algorithms that can be used for string matching, including the Boyer-Moore algorithm and the Brute Force algorithm. The Boyer-Moore algorithm is a string matching algorithm published by Robert S. Boyer and J. Strother Moore in 1977. This algorithm is considered the most efficient algorithm in general applications. The Boyer-Moore algorithm starts matching characters from the pattern on the right. While the Brute Force algorithm is an algorithm that matches a pattern with all text between 0 and n-m to find the existence of a pattern in the text. These two algorithms have different patterns in the search process. In this article, a comparative analysis of the performance of the Boyer-Moore and Brute Force algorithms is carried out in a case study of the search for the Big Indonesian Dictionary (KBBI) based on Android. The search process is carried out by searching based on words and word descriptions. The results of this study indicate that the criteria for running time, the Brute Force algorithm is faster than the Boyer-Moore algorithm with the total running time of the Brute Force algorithm is 168.3 ms in words, 6994.16 ms in word descriptions, while the Boyer-Moore algorithm for running time reached 304.7 ms on the word, 8654.77 ms on the word description. In the testing criteria based on related keywords, the two algorithms can display the same list of related keywords.

scholarly journals Secure Remote User Authentication using Pass Script & Pass Text

2019 ◽  
Vol 8 (4) ◽  
pp. 4411-4417
Keyword(s):  
Smart Card ◽  
Mobile Device ◽  
User Authentication ◽  
Brute Force ◽  
Brute Force Search ◽  
Secure Systems ◽  
Graphical Passwords ◽  
Remote User Authentication ◽  
Remote User

Authenticating users to secure systems is a crucial task for security experts to solve a password problem, where user should able to memorize a password or secret and password should be hard to guess and crack by adversaries. In general, Most of the secure systems were designed with text passwords along with additional factors such as tokens like smart card, mobile device. Text passwords are not resistant to dictionary, brute-force and guessing attacks. This paper proposes a novel graphical password method, which solves the password problem and secure against all password vulnerabilities. Theoretically, graphical passwords are easy to memorize and recall them easily for long term and resistant to dictionary and brute-force search attacks

scholarly journals A Classical Mechanism for Shor's Algorithm Implementations

2018 ◽  
Vol 10 (4) ◽  
pp. 24
Author(s):  
David L. Selke
Keyword(s):  
Random Number ◽  
Random Number Generation ◽  
Brute Force ◽  
Design Intent ◽  
Brute Force Search ◽  
Number Generation ◽  
Shor's Algorithm ◽  
Classical Mechanism

Loops that enforce a correct output and that restart with a changed parameter may emulate a brute force search, even against the design intent. A Python program is presented analogous to Shor's Algorithm but with random number generation replacing the math. It factors integers. Shor's Algorithm devices may operate similarly to the Python program, not in being random, but in being classical.

scholarly journals Generation of macro-operators via investigation of action dependencies in plans

2010 ◽  
Vol 25 (3) ◽  
pp. 281-297 ◽  
Author(s):  
Lukáš Chrpa
Keyword(s):  
Brute Force ◽  
Search Methods ◽  
Brute Force Search ◽  
Useful Knowledge ◽  
Planning Algorithms ◽  
Planning Problems ◽  
Complex Planning

AbstractThere are many approaches for solving planning problems. Many of these approaches are based on ‘brute force’ search methods and they usually do not care about structures of plans previously computed in particular planning domains. By analyzing these structures, we can obtain useful knowledge that can help us find solutions to more complex planning problems. The method described in this paper is designed for gathering macro-operators by analyzing training plans. This sort of analysis is based on the investigation of action dependencies in training plans. Knowledge gained by our method can be passed directly to planning algorithms to improve their efficiency.

scholarly journals Efisiensi Algoritma dan Notasi O-Besar

2011 ◽  
Vol 2 (2) ◽  
pp. 849 ◽  
Author(s):  
Subandijo Subandijo
Keyword(s):  
Time Complexity ◽  
Space Complexity ◽  
Brute Force ◽  
Running Time ◽  
Complexity Function

Efficiency or the running time of an algorithm is usually calculated with time complexity or space complexity as a function of various inputs. It is common to estimate their complexity in the asymptotic sense, i.e., to estimate the complexity function for arbitrarily large input. Brute-force algorithm is the easiest way to calculate the performance of the algorithm. However, it is not recommended since it does not sufficiently explain the efficiency of the algorithm. Asymptotic estimaties are used because different implementations of the same algorithm may differ in efficiency. The big-O notation is used to generate the estimation. 

scholarly journals THE PARALLEL IMPLEMENTATION OF ALGORITHMS FOR FINDING THE REFLECTION SYMMETRY OF THE BINARY IMAGES

2017 ◽  
Vol XLII-2/W4 ◽  
pp. 179-184
Author(s):  
S. Fedotova ◽  
O. Seredin ◽  
O. Kushnir
Keyword(s):  
Symmetry Axis ◽  
Parallel Implementation ◽  
Search Algorithm ◽  
Experimental Studies ◽  
Ground Truth ◽  
Approximate Symmetry ◽  
Brute Force ◽  
Brute Force Search ◽  
Binary Images ◽  
The Common

In this paper, we investigate the exact method of searching an axis of binary image symmetry, based on brute-force search among all potential symmetry axes. As a measure of symmetry, we use the set-theoretic Jaccard similarity applied to two subsets of pixels of the image which is divided by some axis. Brute-force search algorithm definitely finds the axis of approximate symmetry which could be considered as ground-truth, but it requires quite a lot of time to process each image. As a first step of our contribution we develop the parallel version of the brute-force algorithm. It allows us to process large image databases and obtain the desired axis of approximate symmetry for each shape in database. Experimental studies implemented on “Butterflies” and “Flavia” datasets have shown that the proposed algorithm takes several minutes per image to find a symmetry axis. However, in case of real-world applications we need computational efficiency which allows solving the task of symmetry axis search in real or quasi-real time. So, for the task of fast shape symmetry calculation on the common multicore PC we elaborated another parallel program, which based on the procedure suggested before in (Fedotova, 2016). That method takes as an initial axis the axis obtained by superfast comparison of two skeleton primitive sub-chains. This process takes about 0.5 sec on the common PC, it is considerably faster than any of the optimized brute-force methods including ones implemented in supercomputer. In our experiments for 70 percent of cases the found axis coincides with the ground-truth one absolutely, and for the rest of cases it is very close to the ground-truth.

scholarly journals Algorithm to Estimate Direction of Arrival with Interpolated Array Elements for Coprime Array Holes

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Guicai Yu
Keyword(s):  
Degrees Of Freedom ◽  
Signal To Noise Ratio ◽  
Direction Of Arrival ◽  
Array Element ◽  
Regular Pattern ◽  
Minimum Number ◽  
Virtual Array ◽  
Novel Method ◽  
Coprime Arrays ◽  
Coprime Array

A novel method for adding antennas in the coprime arrays is introduced in this study, in order to solve the problem of the reduced degree of freedom of the array in the hole-existing coprime arrays. The minimum number of antennas interpolated in the algorithm maximizes the available degrees of freedom of virtual arrays, and the number of interpolated antennas does not change the original aperture size of the coprime arrays. With the proposed algorithm, the estimate of the direction of arrival is more accurate for a given signal-to-noise ratio. The scheme first finds the regular pattern of hole positions in virtual array elements, and then, according to the regular pattern, the position of the hole of the partial virtual array element is interpolated with the array element antenna at the position of the corresponding coprime arrays. The holes of the virtual array element are filled, giving virtual uniform continuous array elements with maximum degrees of freedom. We use the ESPRIT, and the simulation results show that the proposed algorithm improves the accuracy and resolution of estimates of the direction of arrival.

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