Be concise.
Be useful.
All contributions dictatorially edited by webmasters to match personal tastes.
Please do not paste any copyright violating material.
Please try to avoid dependencies to third-party libraries and frameworks.
func memoize[T comparable, U any](f func(T) U) func(T) U {
memory := make(map[T]U)
return func(t T) U {
if u, seen := memory[t]; seen {
return u
}
u := f(t)
memory[t] = u
return u
}
}memoize is generic but requires that f accepts a single argument of type T and returns a single result of type U.
type
TCache = specialize TFPGMap<TKey, TData>;
var
Cache: TCache;
...
function m(Key: TKey): TData;
begin
if not Assigned(Cache) then
Cache := TCache.Create;
if not Cache.TryGetData(Key, Result) then
begin
Result := f(Key);
Cache.Add(Key, Result);
end;
end;
TKey and TData can be of any kind (as long as they are not a class).
The variable Cache should be freed upon exiting the program.
The variable Cache should be freed upon exiting the program.
my %cache;
sub fib {
my $n = shift;
return $cache{$n} if exists $cache{$n};
return $cache{$n} = $n if $n < 2;
return $cache{$n} = fib($n-1) + fib($n-2);
}
print "\n\nCustom memoized implementation\n";
foreach my $n ( 1..10 ) {
print ' ' . fib( $n );
}
Custom memoization of a Fibonacci function, using a hash to cache result values. Should work for any pure function; i.e. stateless and with no side-effects.
sub f {
my $n = shift;
return $n if $n < 2;
f($n-1) + f($n-2);
}
memoize('f');
print "\n\nFast implementation using CPAN Memoization\n";
foreach my $n ( 1..10 ) {
print ' ' . f( $n );
}
CPAN module Memoize can be used to replace a subroutine with a memoized version. See doc for details.
@functools.lru_cache
def m(*args):
return f(*args)
Function f may have multiple parameters which must be hashable.