Merge Sort
Revision as of 10:34, 8 February 2008 by Xaviar Czervik (talk | contribs) (Changed code to be in <lsl>.)
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Created by Xaviar Czervik. Do whatever you wish with this function: Sell it (good luck), use it, or modify it.
This code sorts a list through use of a Merge Sort. I have no idea why you would want to use it as it is more than 150 times slower than llListSort(), but it is a good demonstration of how a Merge Sort works.
I realize I shouldn't be using iteration in a recursive method... Sue me.
<lsl> list sort(list l) {
if (llGetListLength(l) > 1) { integer mid = llGetListLength(l)/2; list l2 = sort(llList2List(l, 0, mid-1)); list l3 = sort(llList2List(l, mid, -1)); return merge(l2, l3); } return l;
}
list merge(list l, list r) {
integer lm = llGetListLength(l); integer rm = llGetListLength(r); integer lc; integer rc; list ret; while (lc < lm || rc < rm) { if (lc >= lm) { ret += llList2Integer(r, rc); rc++; } else if (rc >= rm) { ret += llList2Integer(l, lc); lc++; } else { if (llList2Integer(l, lc) <= llList2Integer(r, rc)) { ret += llList2Integer(l, lc); if (lc < lm) lc++; } else { ret += llList2Integer(r, rc); if (rc < rm) rc++; } } } return ret;
} </lsl>