update cuckoo link

use webarchive to link to the cycle detection paper by Kervinck.

closes https://github.com/official-stockfish/Stockfish/pull/4389

No functional change

diff --git a/src/position.cpp b/src/position.cpp
index cfd98f686e03ac21ef013437d91cb7d636fd24ef..37aa2e9edec97b3812f646d4f38da67168e0b4a5 100644 (file)
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -97,7 +97,7 @@ std::ostream& operator<<(std::ostream& os, const Position& pos) {
 
 // Marcel van Kervinck's cuckoo algorithm for fast detection of "upcoming repetition"
 // situations. Description of the algorithm in the following paper:
-// https://marcelk.net/2013-04-06/paper/upcoming-rep-v2.pdf
+// http://web.archive.org/web/20201107002606/https://marcelk.net/2013-04-06/paper/upcoming-rep-v2.pdf
 
 // First and second hash functions for indexing the cuckoo tables
 inline int H1(Key h) { return h & 0x1fff; }