  |
perl でバカ正直に書いたらこうなった。%seen で過去の登場分をメモって枝刈りしてみたけど、効果を発揮できてるんだかどうだか分からん。
use strict;
my $found = 0;
my %seen = ();
for my $m (2 .. 7110) {
for my $n (1 .. $m / 2) {
if (find_7110($n, $m - $n)) {
printf "found: %d, %d\n", $n, $m - $n;
$found = 1;
}
}
exit if $found;
}
print "not found.";
exit;
sub find_7110 {
my ($n1, $n2, $x) = @_;
while (($x = $n1 + $n2) < 7110) {
my $k = "$n1 + $n2";
return 0 if exists $seen{$k}; # not found
$seen{$k} = 1;
$n1 = $n2;
$n2 = $x;
}
return ($x == 7110);
}
10
