feat(puzzles, arrays): max consecutive ones

Author: BrianLusina

puzzles/arrays/max_consecutive_ones/README.md

@@ -19,6 +19,16 @@ Explanation: [0,0,1,1,*1*,*1*,1,1,1,*1*,1,1,0,0,0,1,1,1,1]
 starred numbers were flipped from 0 to 1. The longest subarray is [1,1,1,1,1,1,1,1,1,1].
 ```
 
+## Max consecutive ones two
+
+You are given a binary array nums (an array that contains only 0s and 1s). Your task is to find the maximum number of 
+consecutive 1s in the array and return it.
+
+### Constraints
+
+- 1 ≤ `nums.length` ≤ 10^3
+- `nums[i` is either 0 or 1
+
 ## Related Topics
 
 - Array

puzzles/arrays/max_consecutive_ones/__init__.py

@@ -20,3 +20,36 @@ def longest_ones(nums: List[int], k: int) -> int:
             left += 1
 
     return right - left + 1
+
+def find_max_consecutive_ones(nums: List[int]) -> int:
+    """
+    Finds the maximum consecutive ones in a binary array and returns it.
+
+    The most straightforward way to solve this is to use a single pass through the array, keeping track of two values
+    as we go. First, we need a counter for the current streak of consecutive 1s we're seeing. Second, we need to
+    remember the maximum streak we've encountered so far.
+
+    As we examine each element, if we see a 1, we increment our current streak counter. If we see a 0, that breaks our
+    streak, so we reset the counter to 0. Importantly, every time we update our current streak, we check whether it's
+    larger than our maximum and update the maximum if needed.
+
+    Time complexity is O(n) where n is the length of the input array
+    Space complexity is O(1) as no extra space is required
+
+    Args:
+        nums(list): a list of 1s and 0s.
+    Returns:
+        int: maximum number of consecutive 1s in the nums binary array
+    """
+    if len(nums) == 0:
+        return 0
+    max_ones = 0
+    current_consecutive = 0
+
+    for num in nums:
+        if num == 1:
+            current_consecutive += 1
+            max_ones = max(max_ones, current_consecutive)
+        else:
+            current_consecutive = 0
+    return max_ones

puzzles/arrays/max_consecutive_ones/test_max_consecutive_ones.py

@@ -1,23 +1,29 @@
 import unittest
-
-from . import longest_ones
+from typing import List
+from parameterized import parameterized
+from puzzles.arrays.max_consecutive_ones import longest_ones, find_max_consecutive_ones
 
 
 class MaxConsecutiveOnesTestCase(unittest.TestCase):
-    def test_one(self):
-        """should return 6 from nums = [1,1,1,0,0,0,1,1,1,1,0], k = 2"""
-        nums = [1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0]
-        k = 2
-        expected = 6
+
+    @parameterized.expand([
+        ([1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0], 2, 6),
+        ([0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 1, 0, 0, 0, 1, 1, 1, 1], 3, 10),
+    ])
+    def test_longest_ones(self, nums: List[int], k: int, expected: int):
         actual = longest_ones(nums, k)
         self.assertEqual(expected, actual)
 
-    def test_two(self):
-        """should return 10 from nums = [0,0,1,1,0,0,1,1,1,0,1,1,0,0,0,1,1,1,1], k = 3"""
-        nums = [0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 1, 0, 0, 0, 1, 1, 1, 1]
-        k = 3
-        expected = 10
-        actual = longest_ones(nums, k)
+    @parameterized.expand([
+        ([1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0], 4),
+        ([0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 1, 0, 0, 0, 1, 1, 1, 1], 4),
+        ([1,1,0,0,1,1,1,0,0,1,0], 3),
+        ([1,1,0,0,1,1], 2),
+        ([1,1,1,0,1,1,1,1], 4),
+        ([0,0,0,0], 0),
+    ])
+    def test_find_max_consecutive_ones(self, nums: List[int], expected: int):
+        actual = find_max_consecutive_ones(nums)
         self.assertEqual(expected, actual)