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---
id: 5a23c84252665b21eecc801c
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title: Matriz espiral
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challengeType: 5
forumTopicId: 302321
dashedName: spiral-matrix
---
# --description--
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Produza um array espiral. Um *array espiral* é um arranjo quadrado dos primeiros N< sup > 2</ sup > números naturais, onde os números aumentam sequencialmente à medida que você vai visitando as arestas do array em uma espiral para dentro. Por exemplo, dado **5** , produza este array:
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< pre >
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
< / pre >
# --hints--
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`spiralArray` deve ser uma função.
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```js
assert(typeof spiralArray == 'function');
```
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`spiralArray(3)` deve retornar um array.
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```js
assert(Array.isArray(spiralArray(3)));
```
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`spiralArray(3)` deve retornar `[[0, 1, 2],[7, 8, 3],[6, 5, 4]]` .
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```js
assert.deepEqual(spiralArray(3), [
[0, 1, 2],
[7, 8, 3],
[6, 5, 4]
]);
```
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`spiralArray(4)` deve retornar `[[0, 1, 2, 3],[11, 12, 13, 4],[10, 15, 14, 5],[9, 8, 7, 6]]` .
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```js
assert.deepEqual(spiralArray(4), [
[0, 1, 2, 3],
[11, 12, 13, 4],
[10, 15, 14, 5],
[9, 8, 7, 6]
]);
```
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`spiralArray(5)` deve retornar `[[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]]` .
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```js
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]
]);
```
# --seed--
## --seed-contents--
```js
function spiralArray(n) {
}
```
# --solutions--
```js
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;
}
```