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---
id: 594810f028c0303b75339ad8
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title: Zig-zag matrix
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challengeType: 5
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forumTopicId: 302348
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---
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# --description--
A 'zig-zag' array is a square arrangement of the first $N^2$ integers, where the numbers increase sequentially as you zig-zag along the array's [anti-diagonals ](https://en.wiktionary.org/wiki/antidiagonal ).
For example, for the input `5` , the following result should be produced:
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< pre >
0 1 5 6 14
2 4 7 13 15
3 8 12 16 21
9 11 17 20 22
10 18 19 23 24
< / pre >
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# --instructions--
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Write a function that takes the size of the zig-zag matrix, and returns the corresponding matrix as two-dimensional array.
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# --hints--
ZigZagMatrix should be a function.
```js
assert.equal(typeof ZigZagMatrix, 'function');
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```
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ZigZagMatrix should return array.
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```js
assert.equal(typeof ZigZagMatrix(1), 'object');
```
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ZigZagMatrix should return an array of nested arrays.
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```js
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assert.equal(typeof ZigZagMatrix(1)[0], 'object');
```
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ZigZagMatrix(1) should return \[[0]].
```js
assert.deepEqual(ZigZagMatrix(1), zm1);
```
ZigZagMatrix(2) should return \[[0, 1], [2, 3]].
```js
assert.deepEqual(ZigZagMatrix(2), zm2);
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```
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ZigZagMatrix(5) should return specified matrix.
```js
assert.deepEqual(ZigZagMatrix(5), zm5);
```
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# --seed--
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## --after-user-code--
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```js
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const zm1 = [[0]];
const zm2 = [[0, 1], [2, 3]];
const zm5 = [
[0, 1, 5, 6, 14],
[2, 4, 7, 13, 15],
[3, 8, 12, 16, 21],
[9, 11, 17, 20, 22],
[10, 18, 19, 23, 24]
];
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```
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## --seed-contents--
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```js
function ZigZagMatrix(n) {
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return [[], []];
}
```
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# --solutions--
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```js
function ZigZagMatrix(n) {
const mtx = [];
for (let i = 0; i < n ; i + + ) {
mtx[i] = [];
}
let i = 1;
let j = 1;
for (let e = 0; e < n * n ; e + + ) {
mtx[i - 1][j - 1] = e;
if ((i + j) % 2 === 0) {
// Even stripes
if (j < n ) j + + ;
else i += 2;
if (i > 1) i--;
} else {
// Odd stripes
if (i < n ) i + + ;
else j += 2;
if (j > 1) j--;
}
}
return mtx;
}
```