Step 1: evolve a room full of monkeys.

Step 2: give the monkeys your input string.

Step 3: wait.

Eventually the monkeys will generate all possible permutations of your input string. If your input string consists of a large enough pile of alphabet blocks, eventually they may give you the complete works of William Shakespeare as well.

If your monkeys starve to death before the algorithm completes, repeat step 1.

I think you might encounter the thermal death of the universe before the algorithm completes, but if that happens, don't come looking for me. :)