ASD Pb 8 perm fixe

/** p8 permutari elemente pare fixe */
#include<stdio.h>
#include<stdlib.h>
#include<conio.h>


int sol[20], n = 6;//globale
void afisare() {
    for (int i = 1; i <= n; i++) {
        printf("%3d", sol[i]);
    }
    printf("\n");
}

//pozitiile pare raman neschimbate
int valid3(int k) {// sau bool
    for (int i = 1; i < k; i++) {
        if (sol[k] == sol[i])
            return 0;
    }

    if (k % 2 == 1 && sol[k] != k)
        return 0;
    return 1;
}

void bkt(int k) {

    for (int i = 1;i <= n;i++) {
        sol[k] = i;
        if (valid3(k)) {
            if (k == n) {

                afisare();
            }

            else bkt(k + 1);
        }
    }
}

//cresc desc adaugam conditii, conditii de unicitate si cond ca pana la jum sa fie cresc/descresc si invers
int main() {


    bkt(1);
    printf("-------");

    _getch();
    return 0;
}