#1493

Longest Subarray of 1's After Deleting One Element

Medium
ArrayDynamic ProgrammingSliding WindowSliding WindowTwo Pointers
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Approaches

Brute ForceOptimal
Complexity Comparison
Brute ForceOptimal Solution
Time
O(n²)
O(n)
Space
O(1)
O(1)
💡

Intuition

Time O(n)Space O(1)

The optimal approach uses a sliding window technique to maintain a window that contains at most one zero. This way, we can efficiently find the longest subarray of 1's after deleting one element.

⚙️

Algorithm

5 steps
  1. 1Step 1: Initialize two pointers (left and right) and a variable to count zeros.
  2. 2Step 2: Expand the right pointer to include elements in the window until we encounter more than one zero.
  3. 3Step 3: If the count of zeros exceeds one, move the left pointer to shrink the window until we have at most one zero.
  4. 4Step 4: Calculate the length of the current valid window and update the maximum length.
  5. 5Step 5: Return the maximum length found.
solution.py13 lines
1def longestSubarray(nums):
2    left = 0
3    max_length = 0
4    zero_count = 0
5    for right in range(len(nums)):
6        if nums[right] == 0:
7            zero_count += 1
8        while zero_count > 1:
9            if nums[left] == 0:
10                zero_count -= 1
11            left += 1
12        max_length = max(max_length, right - left)
13    return max_length

Complexity note: The time complexity is O(n) because we traverse the array with two pointers, each moving at most n times, leading to a linear scan.

  • 1Using a sliding window allows us to efficiently manage the count of zeros.
  • 2We can find the longest subarray by adjusting the window size dynamically.

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