LC 54 Spiral Matrix

Implementation

// 54. Spiral Matrix
// Given an m x n matrix, return all elements of the matrix in spiral order.

const spiralOrder = matrix => {
  if (!matrix.length || !matrix[0].length) return [];

  const result = [];
  let top = 0;
  let bottom = matrix.length - 1;
  let left = 0;
  let right = matrix[0].length - 1;

  while (top <= bottom && left <= right) {
    for (let col = left; col <= right; col++) result.push(matrix[top][col]);
    top++;

    for (let row = top; row <= bottom; row++) result.push(matrix[row][right]);
    right--;

    if (top <= bottom) {
      for (let col = right; col >= left; col--) result.push(matrix[bottom][col]);
      bottom--;
    }

    if (left <= right) {
      for (let row = bottom; row >= top; row--) result.push(matrix[row][left]);
      left++;
    }
  }

  return result;
};

console.log(spiralOrder([[1, 2, 3], [4, 5, 6], [7, 8, 9]]));
console.log(spiralOrder([[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]]));

export { spiralOrder };

Tests

// Test stub for 04.54.SpiralMatrix

describe('04.54.SpiralMatrix', () => {
  it('should have a test stub', () => {
    expect(true).toBe(true);
  });
});