• Declaring, instanciating, initializing a 2D Array

  • Declare ————————- O(1)

    • dataType[][] arr
    • ex: int[][] arr

  • Instanciation of Array ————————-O(1)

    • arrayRefVar = new datatype[row][col];
    • ex: arr = new int[2][3];

  • Initialization ————————–O(mn)

    • a[0][0]=10;
    • a[0][1]=20;
    • a[0][2]=30;
    • a[1][0]=40;
      ….
  • Declaring, instanciating, initializing ———–O(1)
    1
    * int[][] arr = {{1,2,3},{4,5,6}};

  • When to Use/Avoid Array

    • When to use

      • When there is a need to store multiple similar type of data
      • When random access is regular affair(접근할 때 바로 인덱스 넣으면 접근가능하기에 time complexity가 O(1)이다)

    • When to avoid

      • Data to be stored are non-homogenous(데이터 종류가 같지 않을 경우)
      • When number of data to be stored is not known in advance.