### 498 Diagonal Traverse

```/**
*
* Ashish Patel
* e: ashishsushilPatel@gmail.com
* w: https://ashish.me
*
*/

/*
* Given a matrix of M x N elements (M rows, N columns), return all elements of the matrix
* in diagonal order as shown in the below image.
*
* Example:
*
* Input:
* [
*  [ 1, 2, 3 ],
*  [ 4, 5, 6 ],
*  [ 7, 8, 9 ]
* ]
*
* Output:  [1,2,4,7,5,3,6,8,9]
*/

function diagonalTraverse(matrix) {
if (matrix.length < 1 || matrix[0].length < 1) return []
let res = []
let i = 0,
j = 0,
m = matrix.length,
n = matrix[0].length
for (let k = 0; k < m * n; k++) {
res.push(matrix[i][j])
if ((i + j) % 2 === 0) {
if (j === n - 1) {
i++
} else if (i === 0) {
j++
} else {
i--
j++
}
} else {
if (i === m - 1) {
j++
} else if (j === 0) {
i++
} else {
j--
i++
}
}
}
return res
}

test('diagonal Traverse', () => {
expect(
diagonalTraverse([
[1, 2, 3],
[4, 5, 6],
[7, 8, 9],
]),
).toEqual([1, 2, 4, 7, 5, 3, 6, 8, 9])
expect(diagonalTraverse([[2, 3]])).toEqual([2, 3])
})```

Created 2020-04-09T20:31:46+00:00 · Edit