Join David Powers for an in-depth discussion in this video Detecting horizontal attacks programmatically, part of Code Clinic: PHP.
- In Chess, queens can attack…horizontally, vertically and diagonally.…We've eliminated the first two possibilities by using…binary numbers to represent each row.…There are eight binary numbers, each with only one bit set.…This ensures no two queens are ever…in the same row or column, it's easier to see…if you remove the zeroes.…That means that we only have to check for diagonal attacks.…Let's say there is a queen in the fifth column…of the fourth row, if we check the board row by row…beginning at the top, we need to search…for potential attacks only upwards and left…and upwards and right, diagonal attacks…from the adjacent row come from the column…on either side of the target, attacks from two rows away…come from squares two columns away and so on.…
Diagonals are always an equal number…of rows and columns from the target.…Let's see how we can test adjacent rows.…This is the first row with a binary number…from one of the permutations, we need…to test it against the second row.…Diagonal attacks against the queen in the second row…
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
- Mark as unwatched
- Mark all as unwatched
Are you sure you want to mark all the videos in this course as unwatched?
This will not affect your course history, your reports, or your certificates of completion for this course.Cancel
Take notes with your new membership!
Type in the entry box, then click Enter to save your note.
1:30Press on any video thumbnail to jump immediately to the timecode shown.
Notes are saved with you account but can also be exported as plain text, MS Word, PDF, Google Doc, or Evernote.