+{
+ foreach my $islandname (sort keys %{ $route_mysteries{$oceanname} }) {
+ warn "$route_mysteries{$oceanname}{$islandname} routes".
+ " for unknown island $islandname\n";
+ }
+
+ dbdoall(<<END)
+ CREATE TEMPORARY TABLE newdists (
+ aiid INTEGER NOT NULL,
+ biid INTEGER NOT NULL,
+ dist INTEGER NOT NULL
+ );
+ INSERT INTO newdists SELECT (aiid,biid,dist) FROM dists;
+ INSERT INTO newdists SELECT (biid,aiid,dist) FROM dists;
+ INSERT INTO newdists SELECT (islandid,islandid,0) FROM islands;
+END
+ ;
+
+ my $sth= $dbh->prepare(<<'END')
+ INSERT INTO newdists VALUES
+ ((SELECT islandid FROM islands WHERE islandname == ?),
+ (SELECT islandid FROM islands WHERE islandname == ?),
+ ?);
+END
+ ;
+ my $allroutes= $routes{$oceanname};
+ foreach my $an (keys %$allroutes) {
+ my $routes= $allroutes->{$an};
+ foreach my $bn (keys %$routes) {
+ $sth->execute($an, $bn, $routes->{$bn});
+ }
+ }
+
+ my $stmt_updatemain= $dbh->prepare(<<'END')
+ UPDATE dists SET dist = (
+ SELECT min(dist) FROM newdists
+ WHERE dists.aiid == newdists.aiid
+ AND dists.biid == newdists.biid
+ AND NOT dists.dist <= newdists.dist
+ );
+END
+
+ my $stmt_removeredund= $dbh->prepare(<<'END')
+ DELETE FROM newdists
+ WHERE dist > (
+ SELECT dists.dist
+ WHERE dists.aiid == newdists.aiid
+ AND dists.aiid == newdists.aiid
+ );
+END
+ ;
+
+ my $stmt_gennew= $dbh->prepare(<<'END')
+ INSERT INTO newdists (
+ SELECT src.aiid, dst.biid, min(src.dist + dst.dist)
+ FROM dists AS src, dists AS dst ON src.biid == dst.aiid
+ GROUP BY src.aiid, dst.biid
+ );
+END
+ ;
+
+ for (;;) {
+ $ar= $dbh->selectall_arrayref("select ia.islandname, ib.islandname,newdists.dist from newdists, islands as ia on newdists.aiid = ia.islandid, islands as ib on newdists.biid = ib.islandid;");
+ print Dumper($ar);
+
+ my $affected= $stmt_updatemain->execute();
+ last unless $affected;
+
+ $stmt_
+