**Solution**

**Max Consecutive Ones** https://leetcode.com/problems/max-consecutive-ones/

**Algorithm 1**

- Maintain cnt to track the current run of 1s. Update the max_run after increment of cnt.
- Reset cnt to 0 when we encounter 0 in the array.

```
class Solution(object):
def findMaxConsecutiveOnes(self, nums):
"""
:type nums: List[int]
:rtype: int
"""
max_ones, cnt = 0, 0
for x in nums:
if x == 1:
cnt += 1
max_ones = max(max_ones, cnt)
else:
cnt = 0
return max_ones
```

**Algorithm 2**

- Maintain prev which tracks the index of last seen 0. Initialize prev to -1.
- Do not forget to test for a run after the end of iteration.

```
class Solution(object):
def findMaxConsecutiveOnes(self, nums):
"""
:type nums: List[int]
:rtype: int
"""
prev = -1
max_ones = 0
for i in range(len(nums)):
if nums[i] == 0:
max_ones, prev = max(max_ones, i-prev-1), i
if len(nums) and nums[-1] == 1:
max_ones = max(max_ones, len(nums)-prev-1)
return max_ones
```