[JavaScript] Permutationsとかいう順列（？）の総並べ替えをイテレーションする感じ？（ショボくて使えましぇんよ） ※ https://git.io/vi2Rx が必須

permutation.js

// permutation
// author : Leonardone @ NEETSDKASU
// license: MIT

createPermutationIter = (function() {
    var funcName = "createPermutationIter";
    function errmsg(s) { return "[" + funcName + "] Error! " + s; }
    
    var defaultMethod_getNext = "getNext";
    var defaultMethod_hasNext = "hasNext";
    
    if (parseArguments === undefined) { throw errmsg("require parseArguments function"); }
    
    return function() {
        var method_getNext = defaultMethod_getNext;
        var method_hasNext = defaultMethod_hasNext;
        var size = 0;
        
        parseArguments(arguments, [
            { /* getNext method name */
                "vartype"  : "string",
                "optional" : true,
                "proc"     : function (a) {
                    var obj = new Object();
                    method_getNext = a;
                    if (method_getNext === "") { method_getNext = defaultMethod_getNext; }
                    if (obj[method_getNext]) { throw errmsg("invalid method name of getNext"); }
                }
            },
            { /* hasNext method name */
                "vartype"  : "string",
                "optional" : true,
                "proc"     : function (a) {
                    var obj = new Object();
                    method_hasNext = a;
                    if (method_hasNext === "") { method_hasNext = defaultMethod_hasNext; }
                    if (obj[method_hasNext]) { throw errmsg("invalid method name of hasNext"); }
                    if (method_hasNext === method_getNext) {
                        throw errmsg("same method name both getNext and hasNext");
                    }
                }
            },
            { /* update default method names */
                "vartype"  : "boolean",
                "optional" : true,
                "dependent": [0, 1],
                "proc"     : function (a) {
                    defaultMethod_getNext = method_getNext;
                    defaultMethod_hasNext = method_hasNext;
                }
            },
            { /* permutation size */
                "vartype"  : "number",
                "errmsg"   : errmsg("require permutation size value"),
                "proc"     : function (a) { size = a; }
            }
        ]);
               
        if (size < 2) {
            throw errmsg("illigal size value");
        }
        
        // create permutation iterator
        var flag = new Array(size);
        var indx = new Array(size);
        var dest = new Array(size);
        var existsNext = true;
        var i;
        for (i = 0; i < size; i++) {
            flag[i] = 0;
            indx[i] = i;
        }
        function calcNext() {
            if (!existsNext) { throw errmsg("no next"); }
            if ((dest instanceof Array) === false) {
                dest = new Array(size);
            }
            var i, pos;
            for (i = 0; i < size; i++) {
                dest[i] = indx[i];
            }
            pos = size - 1;
            flag[indx[pos]]++;
            for (;;) {
                pos--;
                if (pos < 0) {
                    existsNext = false;
                    break;
                }
                flag[indx[pos]]++;
                for (i = indx[pos] + 1; i < size; i++) {
                    if (flag[i] > 0) { break; }
                }
                if (i < size) {
                    flag[i]--;
                    indx[pos] = i;
                    pos++;
                    i = 0;
                    while (pos < size && i < size) {
                        if (flag[i] === 0) {
                            i++;
                            continue;
                        }
                        flag[i]--;
                        indx[pos] = i;
                        pos++;
                    }
                    break;
                }
            }
            
            return dest;
        }
        
        return new function() {
            this[method_getNext] = function() {
                return calcNext();
            };
            this[method_hasNext] = function() {
                return existsNext;
            };
        };
    };
})();

test_permutation.html

<!DOCTYPE html>
<html>
<head>
<meta charset="utf8" />
<title>Permutation Demo</title>
<script type="text/javascript" src="./parsearguments.js"></script>
<script type="text/javascript" src="./permutation.js"></script>
</head>
<body>
<h1> Permutation Demo</h1>
<script type="text/javascript">
var piyo = {"log": function(s) {
    document.write("<" + "div"  + ">" + s + "<" + "/" + "div" + ">");
}};

var x = createPermutationIter('hoge', 4);
var i;
for (i = 0; i < 30; i++) {
    if (x.hasNext()) { piyo.log(x.hoge()); }
    else { piyo.log('none'); }
}

/* result
0,1,2,3
0,1,3,2
0,2,1,3
0,2,3,1
0,3,1,2
0,3,2,1
1,0,2,3
1,0,3,2
1,2,0,3
1,2,3,0
1,3,0,2
1,3,2,0
2,0,1,3
2,0,3,1
2,1,0,3
2,1,3,0
2,3,0,1
2,3,1,0
3,0,1,2
3,0,2,1
3,1,0,2
3,1,2,0
3,2,0,1
3,2,1,0
none
none
none
none
none
none
*/

</script>

</body>
</html>

これも車輪の何チャラってやつなんだよにゃあ～

めっちゃ計算コスト高そうな処理になってるにょ～
キョープロ力が弱すぎて計算コストダウンは出来ましぇんえん

以前これと似たようなのc++で作った( https://git.io/vi2zu )けど
今C++の見ると何か色々と酷い出来・・・
つか最近知ったこととしてC++のSTLにはpemutationできる関数が普通にあるとかどうとか・・・

俺以外でこれ使いたい人全くいないと思うけどlicenseを一行入れておいた MIT Licenseなー

The MIT License (MIT)

Copyright (c) 2016 Leonardone @ NEETSDKASU

Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software is furnished to do so,
subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

でも一応これ未完成なんよなー
https://git.io/vi2zu ←こっちでやってた並べ替えパターン生成もやりたいしにゃあ
たしかrubyのpermutationも似たようなことできたと思ったけどー

あー、Javaでもやってたわー
https://git.io/vi226
俺何度車輪やれば気が済むんだぜー

うお、なんかJavaでやったやつnextPattern()がめっちゃシンプルにまとまってんですけど・・・やはり老化で脳みそがダメになったか俺・・・

https://git.io/vi226
このJavaのやつシンプルにまとまってるけど、すっげー非効率なやりかたしてんだな・・・

まぁ今回のJS版のほうがめっちゃ効率いいってほどでもないけど・・・前回のJava版よりはマシなはず・・・！？

何で前回のJavaのEnumeratorやIteratorのインターフェースとか使わなかったのだろうか・・・謎

おいおい、前回のJavaのやつ去年末やんけ・・・まだ1年経っとらんやんけ・・・

new Object()を維持してる意味なさそう

頻繁にメソッド名変えるとかないしね(そもメソッド名変える意味などあるのか)

JS見てて思う
クロージャ(Closure)やべえ