I would like to start by expressing my sincere appreciation for the work that all of you do to maintain Project Euler. I have greatly enjoyed solving some of these problems over the last decade.
This is my first post, and it is quite likely that I am missing something simple here. The problem states that there are 389,488 passwords that are valid on a 3 x 3 grid. I don't understand this; isn't the upper bound for the number of passwords 9! = 362,880?
Thank you for your help.
Problem 879
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As your posts will be visible to the general public you are requested to be thoughtful in not posting anything that might explicitly give away how to solve a particular problem.
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Don't start begging others to give partial answers to problems
Don't ask for hints how to solve a problem
Don't start a new topic for a problem if there already exists one
See also the topics:
Don't post any spoilers
Comments, questions and clarifications about PE problems.
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mdean
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neverforget
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timday
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Re: Problem 879
Is it possible to enter e.g 1-to-6 or 1-to-8 - passing over no intermediate spots - in this interface? Or is it limited to horizontal, vertical and 45-degree diagonal strokes?
(I've seen people using this style of "password" to unlock their phones but I've never tried it myself.)
I imagine reproducing the given 3x3 result will clarify this for me, of course!
(I've seen people using this style of "password" to unlock their phones but I've never tried it myself.)
I imagine reproducing the given 3x3 result will clarify this for me, of course!
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RobertStanforth
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Re: Problem 879
Yes, straight line segments are permitted in any direction.timday wrote: Tue Jul 09, 2024 2:43 pm Is it possible to enter e.g 1-to-6 or 1-to-8 - passing over no intermediate spots - in this interface? Or is it limited to horizontal, vertical and 45-degree diagonal strokes?