Comment on "
Numeric Palindrome Finder in Ruby
"
by
Carl
— Dec 05
Ah, brute force. The other method is to realize that palindromes must be mirror images.
So,
1 -> 11
2 -> 22
…
99 -> 9999
Those are the first 99 palindromes. Then you have issues where the center number is a pivot.
1->101, 111, 121, … 191. (ten items)
Since the limit is 10,000, the largest number you can get with this method is 9 -> 999.
Then add in numbers 0 through 9.
So, my guess is 99 + 90 + 9 = 198. Was I right?
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Numeric Palindrome Finder in Ruby
"
Copyright © Scott Stevenson 2004-2015
by Carl — Dec 05
So,
1 -> 11
2 -> 22
…
99 -> 9999
Those are the first 99 palindromes. Then you have issues where the center number is a pivot.
1->101, 111, 121, … 191. (ten items)
Since the limit is 10,000, the largest number you can get with this method is 9 -> 999.
Then add in numbers 0 through 9.
So, my guess is 99 + 90 + 9 = 198. Was I right?