mark union

void getUnion(int arr1[], int size1, int arr2[], int size2){
    int i,j,f;
    for (i=0;i<size1;i++){
        unionArray[i]=arr1[i];
    }
    for(i=0;i<size2;i++){
            f=1;
        for(j=0;j<size1;j++){
            if (unionArray[i]==arr2[j]){f=-1;}
        }
        if(f==1){
            unionArray[size1+i]=arr2[i];
        }
    }
}