freeCodeCamp/guide/english/certifications/coding-interview-prep/rosetta-code/spiral-matrix/index.md

title

title
Spiral matrix

Spiral matrix

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Solutions

Solution 1 (Click to Show/Hide)

function spiralArray(n) {
  var arr = Array(n),
    x = 0, y = n,
    total = n * n--,
    dx = 1, dy = 0,
    i = 0, j = 0;
  while (y) arr[--y] = [];
  while (i < total) {
    arr[y][x] = i++;
    x += dx; y += dy;
    if (++j == n) {
      if (dy < 0) { x++; y++; n -= 2 }
      j = dx; dx = -dy; dy = j; j = 0;
    }
  }
  return arr;
}