1var assert = require('assert');
2
3function spiraltraverse(inmatrix) {
4  if (!inmatrix.length) return [];
5  const res = [];
6  const dirs = [
7    [0, 1],
8    [1, 0],
9    [0, -1],
10    [-1, 0],
11  ];
12  const scope = [inmatrix[0].length, inmatrix.length - 1];
13  let d = 0,
14    r = 0,
15    c = -1;
16  while (scope[d % 2] > 0) {
17    for (let i = 0; i < scope[d % 2]; i++) {
18      r += dirs[d][0];
19      c += dirs[d][1];
20      res.push(inmatrix[r][c]);
21    }
22    scope[d % 2]--;
23    d = (d + 1) % 4;
24  }
25  return res;
26}
27
28try {
29  assert.equal(
30    spiraltraverse([
31      [1, 2, 3, 4, 5, 6],
32      [7, 8, 9, 10, 11, 12],
33    ]),
34    '1,2,3,4,5,6,12,11,10,9,8,7'
35  );
36
37  console.log(
38    'PASSED: `spiraltraverse([[1,2,3,4,5,6], [7,8,9,10,11,12]])` should return `1,2,3,4,5,6,12,11,10,9,8,7 `'
39  );
40} catch (err) {
41  console.log(err);
42}
43
44try {
45  assert.equal(
46    spiraltraverse([
47      [1, 2, 3, 4],
48      [5, 6, 7, 8],
49      [9, 10, 11, 12],
50      [13, 14, 15, 16],
51    ]),
52    '1,2,3,4,8,12,16,15,14,13,9,5,6,7,11,10'
53  );
54
55  console.log(
56    'PASSED: `spiraltraverse([[1,2,3,4], [5,6,7,8 ], [9,10,11,12], [13,14,15,16]])` should return `1,2,3,4,8,12,16,15,14,13,9,5,6,7,11,10`'
57  );
58} catch (err) {
59  console.log(err);
60}
61
62try {
63  assert.equal(
64    spiraltraverse([
65      [1, 2],
66      [3, 4],
67      [5, 6],
68      [7, 8],
69    ]),
70    '1,2,4,6,8,7,5,3'
71  );
72
73  console.log(
74    'PASSED: `spiraltraverse([[1, 2], [3,4], [5,6], [7,8]])` should return `1,2,4,6,8,7,5,3`'
75  );
76} catch (err) {
77  console.log(err);
78}