On Wed, Jan 8, 2014 at 6:16 PM, Dave Angel <da...@davea.name> wrote: > I can't see the bodies of any of your messages (are you perchance posting > in html? ), but I think there's a good chance you're abusing recursion and > therefore hitting the limit much sooner than necessary. I've seen some code > samples here using recursion to fake a goto, for example. One question to > ask is whether each time you recurse, are you now solving a simpler > problem. > For example, when iterating over a tree you should only recurse when > processing a SHALLOWER subtree. >
Hi Dave: I've been taken to task so often here about having unnecessary chaff in my email replies, that I started getting in the habit of deleting everything (since gmail by (unadjustable) default quotes the entire message string unless you highlight/reply). Since I look at messages in a threaded manner, I wasn't really realizing how much of a pain that was for others. I'm trying to re-establish a highlight/reply habit, like this. I don't THINK I'm misusing recursion, I think I'm just recursing ridiculous things. The problem came in creating palindrome numbers. Apparently, if you add a number to it's reversal (532 + 235), it will be a palindrome, or do it again (with the first result)... with the only mysterious exception of 196, as I understand it. Interestingly, most numbers reach this palindrome state rather quickly: in the first 1000 numbers, here are the number of iterations it takes (numbers don't get credit for being palindromes before you start): {0: 13, 1: 291, 2: 339, 3: 158, 4: 84, 5: 33, 6: 15, 7: 18, 8: 10, 10: 2, 11: 8, 14: 2, 15: 8, 16: 1, 17: 5, 19: 1, 22: 2, 23: 8, 24: 2} Zero stands for where I ran out of recursion depth, set at the time at 9900. Except for the first zero, which is set at 196. It's sort of fascinating: those two 24's both occur in the first 100. So it hardly ever takes any iterations to palindromize a number, except when it takes massive numbers. Except in the single case of 196, where it never, ever happens apparently (though I understand this to not be proven, merely tested out to a few million places). -- Keith
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