Join David Powers for an in-depth discussion in this video Eliminating duplicate solutions, part of Code Clinic: PHP.
- Now that we've seen how to simulate…rotating the chess board,…we can create a routine to eliminate duplicate solutions.…Inside the do-while loop on lines 67 to 71,…I'm going to add a second conditional statement…to check that the current permutation…hasn't already been added to the solutions array.…So a new line on line 69 and then…if not in array we're looking for the…current permutation which is layout…and we want to see if it's in the solutions array,…and line 70 needs to go inside that conditional statement.…
So what this will do is it will add…the current permutation to the solutions array…only if it's not already in the array.…As it stands, this will add everything,…but if we can find the rotations…and add them to the solutions array…before leaving this conditional statement…then we'll be working only with unique solutions.…We haven't defined the function yet,…but we're going to use a function called findRotations.…So findRotations and we'll pass it…the current permutation and the solutions array.…
So once the rotations…
David introduces challenges and provides an overview of his solutions in PHP. Challenges include topics such as statistical analysis, searching directories for images, and accessing peripheral devices.
Visit other courses in the series to see how to solve the exact same challenges in languages like C#, C++, Java, Python, and Ruby.
Skill Level Intermediate
Q: I'm encountering script errors message with the prime_dates.php file used in the "Priming the date_record column" movie in this course. How can I resolve these errors?
A: To avoid script errors, use bindValue() instead of bindParam() in
Line 9 of the prime_dates.php file. You can also download the latest
copy of the exercise files, which corrects this issue for you. For a
more in-depth explanation of the difference between bindValue() and
bindParam(), check out the "Binding input and output values" video (http://www.lynda.com/PHP-
Q: Why can't I access the Lake Pend Orielle site (http://lpo.dt.navy.mil)?
A: The Lake Pend Orielle site is not accessible in some geographical areas. We have contacted the owner of the server to try to resolve this issue.
Q: I am unable to access the Lake Pend Oreille data from outside the U.S.
A: A static copy of this data is provided here for lynda.com members outside of the U.S
Problem One: Statistical Analysis
Problem Two: Image Analysis
Problem Three: Eight Queens
Problem Four: Accessing Peripherals
Problem Five: Recursion and Directories
Problem Six: Building the Web
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