I need to use the Quicksort sorting algorithm to sort elements of a linked list. It is important to note that I must not just swap the key values, but the elements themselves. My code simply does not work; I believe I am making a mistake with the recursion. I would like a solution.

I created the following functions to achieve my goal:

///QUICK SORT///

struct elemento *particiona(struct elemento *ini, struct elemento *fim){

    struct elemento *pivo, *aux, *t1, *t2, *t3, *teste;
    t1 = ini;
    t2 = ini;
    teste = ini;

    int flag = 0;

    /*printf("nini = %dn", ini->chave[0]);
    printf("nfim = %dn", fim->chave[0]);*/

    for(pivo = aux = ini; aux && aux != fim; ) {

        if(aux->chave[0] < fim->chave[0]){

            if(ini != aux){
                pivo = aux;
                flag = 1;

                if(t1 == ini){
                    if(t1 != t2){
                        teste = aux;
                        ini = ini->prox;
                        t1->prox = aux->prox;
                        aux->prox = ini;
                        t2->prox = t1;

                        t1 = aux;
                        aux = t2->prox->prox;
                    }
                    else if(t1 == t2){

                        teste = aux;
                        aux = aux->prox;
                        t1 = t1->prox;
                        t1->prox = ini;
                        ini->prox = aux;
                    }
                }

                else{

                    t1->prox = aux; //10 liga no 5
                    aux = aux->prox; //aux 20
                    t1->prox->prox = ini->prox; //5 liga no 40
                    t2->prox = ini; //10 liga no 50
                    ini = ini->prox; //ini 40
                    t2->prox->prox = aux;
                }
            }

            else{
                ini = ini->prox;
            }
        }


        if(flag == 0)
            aux = aux->prox;
        if(t1 != ini && t1->prox != ini){
            t1 = t1->prox;
        }
        if(t2 != aux && t2->prox != aux)
            t2 = t2->prox;

        flag = 0;
    }

    t1->prox = fim; //50 liga no 20
    t3 = fim->prox; //NULL
    t1->prox->prox = ini->prox; //5 liga no 40
    t2->prox = ini; //10 liga no 50
    ini->prox = t3;

    fim = ini;
    ini = aux;

    printf("npivo = %dn", pivo->chave[0]);*/
    mostrar_chaves(teste);

    return pivo;
}

void quick_sort(struct elemento *ini, struct elemento *fim){

    struct elemento *pivo;
    printf("nINI_Q - %d   FIM_Q - %dn",ini->chave[0], fim->chave[0]);
    if (ini == fim) {
        printf("nreturn estado anteriorn");
        return;
    }
    pivo = particiona(ini, fim);

    if (pivo && pivo->prox) {
        quick_sort(pivo->prox, fim);
    }

    if (pivo && ini != pivo) {
        quick_sort(ini, pivo);
    }
}

struct elemento *fim(struct elemento *ini){
    struct elemento *fim;

    for(fim = ini; fim && fim->prox; fim = fim->prox);

    return fim;
}