/
index.js
47 lines (44 loc) · 1.06 KB
/
index.js
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function allSubsets(arr, branch = [], results = []) {
if (arr.length === 0) {
results.push(branch);
}
if (arr.length > 0) {
const newArr = arr.slice(1);
allSubsets(newArr, [...branch], results);
allSubsets(newArr, [arr[0], ...branch], results);
}
return results;
}
function allPermutations(
arr,
branch = Array.from({ length: arr.length }, () => undefined),
results = []
) {
if (arr.length === 0) {
results.push(branch);
}
if (arr.length > 0) {
branch.forEach((e, idx, b_arr) => {
if (!e) {
const newCombination = [...b_arr];
newCombination[idx] = arr[0];
allPermutations(arr.slice(1), newCombination, results);
}
});
}
return results;
}
function letters(arr) {
return [
...new Set(
allSubsets(arr)
.map((e) => allPermutations(e).map((p) => p.join("")))
.flat()
.filter((e) => !!e)
),
];
}
console.log(letters(["A", "A", "B"]));
console.log(letters(["A", "A", "A", "B"]));
console.log(letters(["A", "B", "C", "D"]));
console.log(letters(["X"]));