[LeetCode] Longest Subarray of 1's After Deleting One Element

題目：Longest Subarray of 1’s After Deleting One Element
難度：Medium

Given a binary array nums, you should delete one element from it.

Return the size of the longest non-empty subarray containing only 1‘s in the resulting array. Return 0 if there is no such subarray.

Example 1:

Input: nums = [1,1,0,1]
Output: 3
Explanation: After deleting the number in position 2, [1,1,1] contains 3 numbers with value of 1’s.

Example 2:

Input: nums = [0,1,1,1,0,1,1,0,1]
Output: 5
Explanation: After deleting the number in position 4, [0,1,1,1,1,1,0,1] longest subarray with value of 1’s is [1,1,1,1,1].

Example 3:

Input: nums = [1,1,1]
Output: 2
Explanation: You must delete one element.

Constraints:

• 1 <= nums.length <= 10^5
• nums[i] is either 0 or 1.

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這題跟這題很像，只要把 k 設為 1 即可
注意，因為無論如何都要移除一個元素，故答案為 j-i-1

時間複雜度：因會遍歷整個矩陣，故時間複雜度為 O(N)，N 為矩陣長度
空間複雜度：因使用的變數為常數，故空間複雜度為 O(1)

public class Solution {
    public int LongestSubarray(int[] nums) {
        int i = 0;
        int j = 0;
        int k = 1;

        while (j < nums.Length)
        {
            if (nums[j] == 0)
            {
                k--;
            }

            if (k < 0)
            {
                if (nums[i] == 0)
                {
                    k++;
                }

                i++;
            }

            j++;
        }

        return j-i-1;
    }
}