void countSort(int tab[], int n, int k) {
    int *counters = new int[k];
    int *result = new int[n];
    for(int i=0; i<k; i++) counters[i] = 0;

for(int i=0;i<n;i++) counters[tab[i]]++;
for(int i=1;i<10;i++) counters[i]+=counters[i-1];
for(int i=n-1;i>=0;i--)result[--counters[tab[i]]]=tab[i];
for(int i=0;i<n;i++)tab[i]=result[i];
    delete [] counters;
    delete [] result;
}