2.6 KiB
2.6 KiB
id | title | challengeType |
---|---|---|
5a23c84252665b21eecc801c | Spiral matrix | 5 |
Description
0 1 2 3 4 15 16 17 18 5 14 23 24 19 6 13 22 21 20 7 12 11 10 9 8
Instructions
Tests
tests:
- text: <code>spiralArray</code> should be a function.
testString: assert(typeof spiralArray=='function','<code>spiralArray</code> should be a function.');
- text: <code>spiralArray(3)</code> should return an array.
testString: assert(Array.isArray(spiralArray(3)), '<code>spiralArray(3)</code> should return an array.');
- text: <code>spiralArray(3)</code> should return <code>[[0, 1, 2],[7, 8, 3],[6, 5, 4]]</code>.
testString: assert.deepEqual(spiralArray(3), [[0, 1, 2], [7, 8, 3], [6, 5, 4]], '<code>spiralArray(3)</code> should return <code>[[0, 1, 2],[7, 8, 3],[6, 5, 4]]</code>.');
- text: <code>spiralArray(4)</code> should return <code>[[0, 1, 2, 3],[11, 12, 13, 4],[10, 15, 14, 5],[9, 8, 7, 6]]</code>.
testString: assert.deepEqual(spiralArray(4), [[0, 1, 2, 3], [11, 12, 13, 4], [10, 15, 14, 5], [9, 8, 7, 6]], '<code>spiralArray(4)</code> should return <code>[[0, 1, 2, 3],[11, 12, 13, 4],[10, 15, 14, 5],[9, 8, 7, 6]]</code>.');
- text: <code>spiralArray(5)</code> should return <code>[[0, 1, 2, 3, 4],[15, 16, 17, 18, 5],[14, 23, 24, 19, 6],[13, 22, 21, 20, 7],[12, 11, 10, 9, 8]]</code>.
testString: assert.deepEqual(spiralArray(5), [[0, 1, 2, 3, 4], [15, 16, 17, 18, 5], [14, 23, 24, 19, 6], [13, 22, 21, 20, 7], [12, 11, 10, 9, 8]], '<code>spiralArray(5)</code> should return <code>[[0, 1, 2, 3, 4],[15, 16, 17, 18, 5],[14, 23, 24, 19, 6],[13, 22, 21, 20, 7],[12, 11, 10, 9, 8]]</code>.');
Challenge Seed
function spiralArray(n) {
// Good luck!
}
Solution
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;
}