[Interview] Print matrix in different ways

Question 1 Print Matrix Diagonal Up Down: 

 Input : 
  [[5 8 9 1],
   [2 7 3 2],
   [0 5 4 9],
   [4 8 7 6]]
 Output : 
  5
  8 2
  9 7 0
  1 3 5 4
  2 4 8
  9 7
  6

 public static void printMatrixDiagonalUpDown(int[][] m){
  int N = m.length;

  for (int i = 0; i<N; i++){
   for (int j =i; j>=0; j--){
    System.out.print(m[i-j][j] + " ");
   }
   System.out.println();
  }

  for (int i = 1; i<N; i++){
   for (int j =N-1; j>=i; j--){
    System.out.print(m[i+N-1-j][j] + " ");
   }
   System.out.println();
  }
 }

Question 2 : Print Matrix Diagonal Down Up
 Input :
  [[5 8 9 1],
   [2 7 3 2],
   [0 5 4 9],
   [4 8 7 6]]
 Output :
  5 
  2 8 
  0 7 9 
  4 5 3 1 
  8 4 2 
  7 9 
  6 

 public void printMatrixDiagonalDownUp(int[][] m){
  int N = m.length;

  for (int i = 0; i<N; i++){
   for (int j =0; j<=i; j++){
    System.out.print(m[i-j][j] + " ");
   }
   System.out.println();
  }

  for (int i = 1; i<N; i++){
   for (int j =i; j<=N-1; j++){
    System.out.print(m[N-1-j+i][j] + " ");
   }
   System.out.println();
  }
 }