1. Do not count the digits of each number one by one.
2. There exist a provable upper limit.
Problem 156
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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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qwarck
- Posts: 3
- Joined: Thu Oct 13, 2016 11:03 am
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v6ph1
- Posts: 134
- Joined: Mon Aug 25, 2014 7:14 pm
Re: Problem 156
A limit until the f(n,d)=n has some solutions.
Numbers n beyond that limit can be easily proven not to be solutions of f(n,d)=n.
Numbers n beyond that limit can be easily proven not to be solutions of f(n,d)=n.
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qwarck
- Posts: 3
- Joined: Thu Oct 13, 2016 11:03 am
Re: Problem 156
I found a way how to calculate f(number, digit=1) for any number without actual counting one-by-one,
but I still can`t see how calculate sum of solutions to the equation f(n,1)=n without iterating through big range of numbers one by one.
but I still can`t see how calculate sum of solutions to the equation f(n,1)=n without iterating through big range of numbers one by one.
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v6ph1
- Posts: 134
- Joined: Mon Aug 25, 2014 7:14 pm
Re: Problem 156
How many ones are in a specific decade, in a range of hundred or thousand?
Think a little bit about this question and you have an idea, where to optimize.
Think a little bit about this question and you have an idea, where to optimize.