 # Cells with Odd Values in a Matrix Lab

Easy
1
18.2% Acceptance

In this lab, you are tasked to implement a function that calculates the number of odd-valued cells in a matrix after applying increment operations. The matrix is an `m x n` matrix, initialized to all `0`'s. There is also a 2D array `indices` where each `indices[i] = [ri, ci]` represents a 0-indexed location to perform some increment operations on the matrix.

For each location `indices[i]`, do both of the following:

1. Increment all the cells on row `ri`.
2. Increment all the cells on column `ci`.

The function should be named `oddCells` and should have the following signature:

``oddCells(m: number, n: number, indices: number[][]): number``

Example 1:

``````Input: m = 2, n = 3, indices = [[0,1],[1,1]]
Output: 6``````

Explanation:

Initial matrix = `[[0,0,0],[0,0,0]]`. After applying first increment it becomes `[[1,2,1],[0,1,0]]`. The final matrix is `[[1,3,1],[1,3,1]]`, which contains 6 odd numbers.

Example 2:

``````Input: m = 2, n = 2, indices = [[1,1],[0,0]]
Output: 0``````

Explanation:

Final matrix = `[[2,2],[2,2]]`. There are no odd numbers in the final matrix.

Constraints:

• `1 <= m, n <= 50`
• `1 <= indices.length <= 100`
• `0 <= ri < m`
• `0 <= ci < n`

### Challenges

1. Implement the `oddCells` function.
2. Export the `oddCells` function using ESM import/export syntax.
3. Optimize your solution to have a time complexity of `O(n + m + indices.length)` with only `O(n + m)` extra space.

Good luck!