If I have one array that contains items , for example
["To","Ti","Ta"]
I would like to have a function that return all permutations of appended items in array, here function would return:
[["ToTiTa"]["ToTaTi"]["TiToTa"]["TiTaTo"]["TaToTi"]["TaTiTo"]]
Could you help me please?
What you are looking for are permutations. You can create them with a recursive function.
The code below is an example. permute is the front-end function, which your code should call. permute_rec is the recursive function that builds the permutation array and swap is just a convenience function for swapping elements in an array:
function swap(array, i, j) {
if (i != j) {
var swap = array[i];
array[i] = array[j];
array[j] = swap;
}
}
function permute_rec(res, str, array) {
if (array.length == 0) {
res.push(str);
} else {
for (var i = 0; i < array.length; i++) {
swap(array, 0, i);
permute_rec(res, str + array[0], array.slice(1));
swap(array, 0, i);
}
}
}
function permute(array) {
var res = [];
permute_rec(res, "", array);
return res;
}
console.log(permute(["A", "B", "C"]));
Edit: You can extend this code to include permutations of subarrays with this code:
function xpermute_rec(res, sub, array) {
if (array.length == 0) {
if (sub.length > 0) permute_rec(res, "", sub);
} else {
xpermute_rec(res, sub, array.slice(1));
xpermute_rec(res, sub.concat(array[0]), array.slice(1));
}
}
function xpermute(array) {
var res = [];
xpermute_rec(res, [], array);
return res;
}
console.log(xpermute(["A", "B", "C"]));
This code creates all subarrays and then uses the original code to create the permutations. (The case of the empty array is skipped.)
xpermute function.