Find the Longest Consecutive Run of Ones

Question

The question asks the candidate to implement a function that finds the longest consecutive run of ones in a binary array.

Codemia · Accepted Answer

To solve the problem of finding the longest consecutive run of ones in a binary array, I will use a simple linear scan approach. This involves iterating through the array while maintaining a count of consecutive ones and updating the maximum count whenever a zero is encountered. This method is efficient and straightforward.

Here is the Python implementation of the approach:

```python
def longest_consecutive_ones(arr):
    max_count = 0
    current_count = 0

for num in arr:
        if num == 1:
            current_count += 1
            max_count = max(max_count, current_count)
        else:
            current_count = 0

return max_count
```
This code initializes two counters: `max_count` to track the longest run of ones and `current_count` to count the current run. It iterates through the array, updating these counters as it encounters ones and zeros.

The time complexity of this solution is O(n), where n is the length of the input array. This is because we perform a single pass through the array. The space complexity is O(1) since we are using a constant amount of extra space for the counters.

It is important to consider edge cases such as:
1. An empty array should return 0.
2. An array with no ones should also return 0.
3. An array that consists entirely of ones should return the length of the array.

Interviewers will be looking for clarity in your explanation and your ability to articulate your thought process. They will also pay attention to how well you handle edge cases and your understanding of time and space complexity. A clean and efficient code implementation is crucial, as well as your ability to discuss potential optimizations.

Find the Longest Consecutive Run of Ones

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