Project Euler/62 - Revision history

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2019-10-09T03:49:22Z

Replacing charlesreid1.com:3000 with git.charlesreid1.com

← Older revision		Revision as of 03:49, 9 October 2019
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	</pre>		</pre>

	Link: https://charlesreid1.com~~:3000~~/cs/euler/src/master/scratch/Round2_050-070/062/Problem062.java		Link: https://git.charlesreid1.com/cs/euler/src/master/scratch/Round2_050-070/062/Problem062.java

	==Flags==		==Flags==

	{{ProjectEulerFlag}}		{{ProjectEulerFlag}}

2018-01-08T10:26:20Z

Code

← Older revision		Revision as of 10:26, 8 January 2018
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	System.out.println("Search for a cube that permutes "+nperms+" times failed. Search stopped at "+MAX+".");		System.out.println("Search for a cube that permutes "+nperms+" times failed. Search stopped at "+MAX+".");
	return null;		return null;
	<pre>		</pre>

	Link: https://charlesreid1.com:3000/cs/euler/src/master/scratch/Round2_050-070/062/Problem062.java		Link: https://charlesreid1.com:3000/cs/euler/src/master/scratch/Round2_050-070/062/Problem062.java

2018-01-08T10:26:08Z

Code

@@ Line 15: / Line 15: @@
 ==Code==
-https://charlesreid1.com:3000/cs/euler/src/master/scratch/Round2_050-070/062/Problem062.java
+The core of the method, where we proceed through the problem in chunks and assemble a hash map to store all of the cubes with N digits:
 ==Flags==
 {{ProjectEulerFlag}}

2018-01-08T10:25:32Z

Solution Technique

← Older revision		Revision as of 10:25, 8 January 2018
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	==Solution Technique==		==Solution Technique==

			We are looking for the smallest cube that permutes with N other cubes.

			The key idea here is that, for a particular cube permuting to other cubes, the cubes must all have the same number of digits - which provides a lower and upper bound on the numbers that need to be examined for a particular cube. This means we can break the problems into chunks, each increasing in size by an order of magnitude, and tackle the problem that way. (For reference, the final result is 12 digits!)

			The core data structure to do this task quickly is the hash map - we proceed by computing a round of <math>10^{N-1}</math> to <math>10^{N}</math> perfect cubes, and sort their digits. These form the hash map keys, and we store the cube that results in a list so that we can cross-reference it in our search for permuted digits.

	==Code==		==Code==

2018-01-08T10:21:37Z

Code

← Older revision		Revision as of 10:21, 8 January 2018
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	==Code==		==Code==

	~~Link:~~ https://charlesreid1.com:3000/cs/euler/src/master/scratch/Round2_050-070/062		https://charlesreid1.com:3000/cs/euler/src/master/scratch/Round2_050-070/062/Problem062.java

	==Flags==		==Flags==

	{{ProjectEulerFlag}}		{{ProjectEulerFlag}}

2018-01-08T10:21:23Z

Problem Statement

← Older revision		Revision as of 10:21, 8 January 2018
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	==Problem Statement==		==Problem Statement==

			Cubes that permute to other cubes: find the smallest cube for which exactly 5 permutations of the cube are also cubes.

	Link: https://projecteuler.net/problem=62		Link: https://projecteuler.net/problem=62

2018-01-08T10:13:59Z

Code

← Older revision		Revision as of 10:13, 8 January 2018
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	==Code==		==Code==

			Link: https://charlesreid1.com:3000/cs/euler/src/master/scratch/Round2_050-070/062

	==Flags==		==Flags==

	{{ProjectEulerFlag}}		{{ProjectEulerFlag}}

2018-01-08T10:11:17Z

Created page with "==Problem Statement== Link: https://projecteuler.net/problem=62 ==Solution Technique== ==Code== ==Flags== {{ProjectEulerFlag}}"

New page

==Problem Statement==

Link: https://projecteuler.net/problem=62

==Solution Technique==

==Code==

==Flags==

{{ProjectEulerFlag}}