Find the Earliest Row with the Most Ones
Company: Amazon
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: easy
Interview Round: Other
### Problem
Given a nonempty binary matrix mat, return [rowIndex, oneCount] for a row containing the most ones. Break ties by choosing the smallest row index. Rows need not be sorted.
```cpp
class Solution {
public:
vector<int> rowAndMaximumOnes(vector<vector<int>>& mat);
};
```
### Examples
**Example 1:**
```text
Input: mat = [[1,0,1],[1,1,0],[0,0,0]]
Output: [0,2]
Explanation: Rows 0 and 1 each contain two ones, so the smaller index wins.
```
**Example 2:**
```text
Input: mat = [[0],[0],[1]]
Output: [2,1]
Explanation: Only the third row contains a one.
```
### Constraints
- `m == mat.length`; `n == mat[i].length`.
- `1 <= m, n <= 100`.
- Each entry is 0 or 1.
### Clarifying Questions
- Are row indices zero-based? Yes.
- How are count ties resolved? Choose the smallest row index.
- Must rows already be sorted? No.
- What is the output order? Row index first, number of ones second.
```hint Check the boundary
Check a matrix containing only zeroes.
```
Overview: Return the smallest-index row with the most ones and its one count, without assuming rows are sorted.
