// Generate all permutations recursively
function permutations(arr, l = 0, r = arr.length - 1) {
if (l === r) {
console.log(arr.join(" "));
return;
}
for (let i = l; i <= r; i++) {
[arr[l], arr[i]] = [arr[i], arr[l]]; // swap
permutations(arr, l + 1, r);
[arr[l], arr[i]] = [arr[i], arr[l]]; // backtrack
}
}
// Generate all combinations using bitmask
function generateCombinations(arr) {
const size = arr.length;
for (let mask = 1; mask < (1 << size); mask++) {
const combo = [];
for (let i = 0; i < size; i++) {
if (mask & (1 << i)) {
combo.push(arr[i]);
}
}
console.log(combo.join(" "));
}
}
function main() {
const input = ["a", "b", "c"];
console.log("All permutations:");
permutations([...input]); // use a copy
console.log("\nAll combinations:");
generateCombinations(input);
}
main();
/*
run:
All permutations:
a b c
a c b
b a c
b c a
c b a
c a b
All combinations:
a
b
a b
c
a c
b c
a b c
*/
