Project Euler/4 - Revision history

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

2019-10-09T03:47:20Z

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

← Older revision		Revision as of 03:47, 9 October 2019
Line 1:		Line 1:
	Problem 4 on Project Euler: https://projecteuler.net/problem=4		Problem 4 on Project Euler: https://projecteuler.net/problem=4

	Solution: https://charlesreid1.com~~:3000~~/cs/euler/src/master/004		Solution: https://git.charlesreid1.com/cs/euler/src/master/004

	Find the largest palindrome that is a product of two three-digit numbers.		Find the largest palindrome that is a product of two three-digit numbers.

Admin: /* Strings and numbers */

2017-07-08T08:39:55Z

Strings and numbers

← Older revision		Revision as of 08:39, 8 July 2017
Line 29:		Line 29:
	** int to char - '0' + i		** int to char - '0' + i
	** int to String - Integer.toString(int)		** int to String - Integer.toString(int)

			[[Category:Java]]


	{{ProjectEulerFlag}}		{{ProjectEulerFlag}}

Admin at 08:39, 8 July 2017

2017-07-08T08:39:29Z

← Older revision		Revision as of 08:39, 8 July 2017
Line 1:		Line 1:
	Problem 4 on Project Euler: https://projecteuler.net/problem=4		Problem 4 on Project Euler: https://projecteuler.net/problem=4

			Solution: https://charlesreid1.com:3000/cs/euler/src/master/004

			Find the largest palindrome that is a product of two three-digit numbers.

	==Notes==		==Notes==
Line 15:		Line 19:
	* Compute the maximum of the set		* Compute the maximum of the set

			==Strings and numbers==

			This is the first of many Project Euler problems in which you'll need to quickly and easily convert from a number representation to a String representation (e.g., to check if a palindrome). Good to keep all of it straight, particularly in Java, since there are primitive types and there are wrappers, and I often find myself going from any of the above to all of the above.
			** char to Chacter or int to Integer - can cast
			** char to int - Character.digit(c)
			** char to Integer - new Integer(Character.digit(c))
			** String to int - Integer.parseInt(s)
			** String to Integer - Integer.parseInt(s)
			** int to char - '0' + i
			** int to String - Integer.toString(int)

	{{ProjectEulerFlag}}		{{ProjectEulerFlag}}

Admin: Admin moved page Project Euler/Largest Palindrome Product to Project Euler/4

2017-07-05T04:08:06Z

Admin moved page Project Euler/Largest Palindrome Product to Project Euler/4

← Older revision	Revision as of 04:08, 5 July 2017
(No difference)

Admin at 09:01, 1 July 2017

2017-07-01T09:01:24Z

← Older revision		Revision as of 09:01, 1 July 2017
Line 1:		Line 1:
	Problem 4 on Project Euler: https://projecteuler.net/problem=4		Problem 4 on Project Euler: https://projecteuler.net/problem=4

			==Notes==

	In this problem, we are asked to find the largest palindrome number that is the product of two three-digit numbers.		In this problem, we are asked to find the largest palindrome number that is the product of two three-digit numbers.
Line 12:		Line 14:
	* Add the product to a set		* Add the product to a set
	* Compute the maximum of the set		* Compute the maximum of the set

Admin at 08:43, 1 July 2017

2017-07-01T08:43:15Z

← Older revision		Revision as of 08:43, 1 July 2017
Line 1:		Line 1:
			Problem 4 on Project Euler: https://projecteuler.net/problem=4

	In this problem, we are asked to find the largest palindrome number that is the product of two three-digit numbers.		In this problem, we are asked to find the largest palindrome number that is the product of two three-digit numbers.

Admin: Created page with "In this problem, we are asked to find the largest palindrome number that is the product of two three-digit numbers. This problem has one main task: * Turning numbers into str..."

2017-07-01T08:42:50Z

Created page with "In this problem, we are asked to find the largest palindrome number that is the product of two three-digit numbers. This problem has one main task: * Turning numbers into str..."

New page

In this problem, we are asked to find the largest palindrome number that is the product of two three-digit numbers.

This problem has one main task:
* Turning numbers into strings (to check if palindrome)

Normally, Project Euler problems present you with a huge, intractable problem space, and you must spend some time up front eliminating or narrowing down the space you are exploring. But in this case, the key space of all products of all three-digit numbers is trivial to generate, so we do it. Then take the maximum.

Basic structure:
* For each combination of three digit numbers:
* Add the product to a set
* Compute the maximum of the set

{{ProjectEulerFlag}}

[[Category:Project Euler]]
[[Category:CS]]
[[Category:Competitive Programming]]