Question

I was solving a problem in which given a linked list of characters , we have to move the vowels to the beginning such that both vowels and consonants are in chronological order. That is in the order in which they appear in original list.

Input : S->T->A->C->K->O->V->E->R->F->L->O->W

Output : A->O->E->O->S->T->C->K->V->R->F->L->W

I did it by traversing through the list once and created two lists called vowels and consonants and later merged them.

Can it be done without creating extra lists ? I mean in-place maybe using pointer manipulation?

Answer 1

Remember the beginning of the list. When you meet a vowel, move it to the beginning of the list; the vowel becomes the new beginning that you remember.