Split an array into two arrays

Question

I need elements of matrix put into an array, then i need to sort first odd numbers and then even numbers Example: This is array: 5, 9, 1, 2, 3, 8, 4. output: 1,3,5,9 ; 2,4,8

This is my code:

int[] array=new int[mat.length*mat[0].length];
int cnt=0;

for(int i=0; i<mat.length; i++)
{
  for(int j=0; j<mat[0].length; j++)
  {
    array[cnt]=mat[i][j];
    cnt++;
  }
}
int cnt1=0;
int cnt2=0;
int[] array1=new int[array.length];
int[] array2=new int[array.length];
for(int i=0; i<array.length; i++)
{
  if(array[i]%2==0)
  {
    array1[br1]=array[i];
    cnt1++;
  }
  else
  {
    array2[br2]=array[i];
    cnt2++;
  }
}

The problem is this two arrays for odd and even numbers, because i don't know their length and if i put the size of whole array, then i will get zeros for remaining places in odd array for number that is even and vice versa. How would you do this? Thank you

Answer 1

If you can use List you can do

List<Integer> even = new ArrayList<>();
List<Integer> odd = new ArrayList<>();

for(int i=0; i<mat.length; i++) {
    for(int j=0; j<mat[0].length; j++) {
        if (mat[i][j] % 2 == 0)
            even.add(mat[i][j]);
        else
            odd.add(mat[i][j]);
    }
}

Collections.sort(even);
Collections.sort(odd);

odd.addAll(even);

for (int v: odd){
    System.out.println(v);
}