Palindrome permutation

[altay9]

#146

[ErdemT09]

Instead of just calling it "-Faster", this time, it's better to call it "-Array" and the previous solution "-HashMap".

[ErdemT09]

Uising 3 valued Java-logic ( Optional<Boolean> )might also be helpful here:
EDIT: We can just do it with normal booleans:

boolean sawSingle = false;
            for (int key = 0; key < map.length; key++) {
                if (map[key] % 2 == 1) {
                    if (sawSingle) {
                        return false;
                    }
                    sawSingle = true;
                }
            }
            return true;
        }

[altay9]

Instead of just calling it "-Faster", this time, it's better to call it "-Array" and the previous solution "-HashMap".

Ok, this is done.

[ErdemT09]

Uising 3 valued Java-logic ( Optional )might also be helpful here:
EDIT: We can just do it with normal booleans:

boolean sawSingle = false;
            for (int key = 0; key < map.length; key++) {
                if (map[key] % 2 == 1) {
                    if (sawSingle) {
                        return false;
                    }
                    sawSingle = true;
                }
            }
            return true;
        }

What do you think about the idea here? Would it work?

[altay9]

Uising 3 valued Java-logic ( Optional )might also be helpful here:
EDIT: We can just do it with normal booleans:

boolean sawSingle = false;
            for (int key = 0; key < map.length; key++) {
                if (map[key] % 2 == 1) {
                    if (sawSingle) {
                        return false;
                    }
                    sawSingle = true;
                }
            }
            return true;
        }

What do you think about the idea here? Would it work?

Yeah, of course. Nice idea:

Even if, Optional class is not that useful in this context, It would be something like that:

           for (int key = 0; key < map.length; key++) {
               if (map[key] % 2 == 1) {
                  if (anExternalBooleanParameter.orElse(false)) {
                           return false;
                      }
                  anExternalBooleanParameter = Optional.of(true);
               }
           }
           return true;

In what kind of context would an Optional be meaningful?
In some cases like; reading the value of anExternalBooleanParameter (or another boolean) from a database or getting it via a REST service; we might not know if it is empty.
For example, It would have been created like this and sent our API method as a parameter in an external service:

Optional<Boolean> anExternalBooleanParameter= Optional.empty();

In that case, we should have given a default value using orElse.

[ErdemT09]

Shall we add the boolean approach to the solution then?

[altay9]

Shall we add the boolean approach to the solution then?

Of course. I will add it too.

[altay9]

Shall we add the boolean approach to the solution then?

Oke, it is done.
https://github.com/spiralgo/algorithms/pull/251/files#diff-0e1e5a4f3753c0ec2228dc6e5d217756506e5cf50310c02360bfac10229a19f6

[ErdemT09]

Approved then.