fn swap(arr: &mut [char], i: usize, j: usize) {
arr.swap(i, j);
}
fn print_array(arr: &[char]) {
for ch in arr {
print!("{} ", ch);
}
println!();
}
// Recursive function to generate permutations
fn permute(arr: &mut [char], l: usize, r: usize) {
if l == r {
print_array(arr);
return;
}
for i in l..=r {
swap(arr, l, i);
permute(arr, l + 1, r);
swap(arr, l, i); // backtrack
}
}
// Generate all combinations using bitmask
fn generate_combinations(arr: &[char]) {
let size = arr.len();
for mask in 1..(1 << size) {
for i in 0..size {
if mask & (1 << i) != 0 {
print!("{} ", arr[i]);
}
}
println!();
}
}
fn main() {
let mut input: Vec<char> = "abc".chars().collect();
let size = input.len();
println!("All permutations:");
permute(&mut input, 0, size - 1);
println!("\nAll combinations:");
generate_combinations(&input);
}
/*
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
*/
