Code Review (Easy): The Guided Grid Tour

Story

Lena is working on a new onboarding feature for the internal dashboard that guides users through grid layouts in a natural, clockwise spiral. Eva suggested that the sequence should start at the top-left corner, wrap around the outer perimeter, and then gradually curl inward until every tile has been visited. For instance, if a user is looking at a three-by-three grid numbered one through nine, the guide would lead them from one through three, down to nine, across to seven, and finally finish at the center. This logic will help ensure no part of the interface is overlooked during the initial setup process.

Your Task

Read the story and code, then decide if the code is ready for production or needs improvement.

Hints

What would block an approval? Give me a hint.

Check out Next Topic: The Grid Organizer

export function spiralOrder(matrix: number[][], useAlternate = false): number[] {
  if (matrix.length === 0 || matrix[0].length === 0) return [];

function classicSpiral(mat: number[][]): number[] {
    const m = mat.length;
    const n = mat[0].length;
    const result: number[] = [];
    let top = 0;
    let bottom = m - 1;
    let left = 0;
    let right = n - 1;

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

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

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

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

return result;
  }

function alternateSpiral(mat: number[][]): number[] {
    const m = mat.length;
    const n = mat[0].length;
    const visited = Array.from({ length: m }, () => Array<boolean>(n).fill(false));
    const result: number[] = [];
    const dirs = [
      [0, 1],
      [1, 0],
      [0, -1],
      [-1, 0],
    ];
    let dir = 0;
    let r = 0;
    let c = 0;

for (let k = 0; k < m * n; k++) {
      result.push(mat[r][c]);
      visited[r][c] = true;
      let nr = r + dirs[dir][0];
      let nc = c + dirs[dir][1];

if (nr < 0 || nr >= m || nc < 0 || nc >= n || visited[nr][nc]) {
        dir = (dir + 1) % 4;
        nr = r + dirs[dir][0];
        nc = c + dirs[dir][1];
      }

r = nr;
      c = nc;
    }

return result;
  }

// The flag controls which internal implementation to run.
  if (useAlternate) {
    return alternateSpiral(matrix);
  } else {
    return classicSpiral(matrix);
  }
}