Combinatory Analysis - Generate n! arrangements

[kalena]

I need an algorithm that manages all possible arrangements for n elements n positions, that is, No! is the amount of possible arrangements, as in the example below:

n = 3
3! = 6 arranjos
123

132

213

231

312

321

I'm trying to create it in JavaScript, but it's not working.

function partida(){

var nc = 4;

var nl = fatorial(nc);

var jogada = new Array(nl);
for (i = 0; i < nl; i++){
    jogada[i] = new Array(nc);
}

for (c = 0; c < nc; c++){
    var q = fatorial(nc - c)/(nc - c);
    for (l = 0; l < nl; l++){
        jogada[l][c] = Math.trunc(l/q) + c;
    }
}

textarea = document.getElementById('arranjos');
for (l = 0; l < nl; l++){
    textarea.innerHTML += (jogada[l].toString()).replace(/,/g, "");
    textarea.innerHTML += '\n';
}

}

[emran]

My response was inspired by this http://marmsx.msxall.com/cursos/c16.html If you want more explanations.

I used three functions to get to the answer.

function buld_char(valor){
    for (var i = 0; i < valor; i++) {
        lista.push(i+1);
    }
    permutacao_recursiva(lista,0);
}

This function will receive a value, which in your case is n and will mount an array with all values from 1 to n. At the end he will call the function permutacao_recursiva();

function permutacao_recursiva(str,k){
    var i, len;
    len = str.length;
if (k == len)
    console.log(str);
else {
    for (i = k; i < len; i++) {
        str = troca_char(str, k, i);
        permutacao_recursiva(str, k + 1);
        str = troca_char(str, i, k);
    }
}

}

Whenever necessary this function will call a third, which will change the characters of the array

function troca_char(str, p1, p2) {

aux = str[p1];

str[p1] = str[p2]

str[p2] = aux;

return str;

}

Having these three functions just declare a global variable

var lista = [];

and call function buld_char(3); passing the value of n