Psst: Open the JavaScript Console and try to play around with these functions:

2-Dimensional Arrays

• const matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]];
• matrix[0][0] // returns 1
• matrix[0][1] // returns 2
• matrix[1][0] // returns 4

2D Array Traversal

• const grid = [
    [1, 2, 3, 4, 5],
    [6, 7, 8, 9, 10],
    [11, 12, 13, 14, 15],
    [16, 17, 18, 19, 20],
    [21, 22, 23, 24, 25],
  ];
          

• for (let row of grid) {
    for (let item of row) {
      console.log(item);
    }
  }
  // should log the ff. into the console:
  // 1, 2, 3, 4, 5,
  // 6, 7, 8, 9, 10,
  // 11, 12, 13, 14, 15,
  // 16, 17, 18, 19, 20,
  // 21, 22, 23, 24, 25
          

• depthFirstSearch2D(grid); // start from 1
  // should return:
  // [1, 2, 3, 4, 5,
  //  10, 15, 20, 25, 24,
  //  19, 14, 9, 8, 13,
  //  18, 23, 22, 17, 12,
  //  7, 6, 11, 16, 21]
          

• depthFirstSearch2D(grid, 2, 2); // start from 13
  // should return:
  // [13, 8, 3, 4, 5,
  // 10, 15, 20, 25, 24,
  // 19, 14, 9, 18, 23,
  // 22, 17, 12, 7, 2,
  // 1, 6, 11, 16, 21]
          

• breadthFirstSearch2D(grid); // start from 1
  // should return:
  // [1, 2, 6, 3, 7,
  //  11, 4, 8, 12, 16,
  //  5, 9, 13, 17, 21,
  //  10, 14, 18, 22, 15,
  //  19, 23, 20, 24, 25]
          

• breadthFirstSearch2D(grid, 2, 2); // start from 13
  // should return:
  // [13, 8, 14, 18, 12,
  //  3, 9, 7, 15, 19,
  //  23, 17, 11, 4, 2,
  //  10, 6, 20, 24, 22,
  //  16, 5, 1, 25, 21]