combination_lock

combination_lock, a MATLAB code which simulates the process of determining the combination of a lock.

This program demonstrates the method of exhaustive search, that is, it searches for an answer by trying every possibility. This requires a way of logically ordering the possibilities.

Usage:

combination_lock ( m, n, c )

• m, the number of dials (perhaps 3).
• n, the number of symbols on each dial (perhaps 10);
• c, a vector of length m, containing the combination, which should be integers in the range 0 to n-1. (perhaps [7,4,9]).

Licensing:

The information on this web page is distributed under the MIT license.

Languages:

combination_lock is available in a C version and a C++ version and a Fortran90 version and a MATLAB version and a Python version.

Related Data and Programs:

combination_lock_test

bicycle_lock, a MATLAB code which simulates the process of determining the secret combination of a bicycle lock, an integer between 000 and 999.

combo, a MATLAB code which includes many combinatorial routines.

partition_problem, a MATLAB code which seeks solutions of the partition problem, splitting a set of integers into two subsets with equal sum.

satisfy_brute, a MATLAB code which uses brute force to find all assignments of values to a set of logical variables which make a complicated logical statement true.

subset, a MATLAB code which enumerates combinations, partitions, subsets, index sets, and other combinatorial objects.

subset_sum, a MATLAB code which seeks solutions of the subset sum problem.

tsp_brute, a MATLAB code which reads a file of city-to-city distances and solves the traveling salesperson problem, using brute force.

Reference:

1. Donald Kreher, Douglas Simpson,
   Combinatorial Algorithms,
   CRC Press, 1998,
   ISBN: 0-8493-3988-X,
   LC: QA164.K73.
2. Silvano Martello, Paolo Toth,
   Knapsack Problems: Algorithms and Computer Implementations,
   Wiley, 1990,
   ISBN: 0-471-92420-2,
   LC: QA267.7.M37.

Source Code:

• combination_lock.m, the program for a general (m,n) combination lock.
• combination_next.m, returns the next combination.
• i4vec_eq.m, returns TRUE if two I4VEC's are equal.
• i4vec_print.m, prints an I4VEC.