Longest Subarray of 1's After Deleting One Element

Description

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.

Example 4:

Input: nums = [1,1,0,0,1,1,1,0,1]
Output: 4

Example 5:

Input: nums = [0,0,0]
Output: 0

 

Constraints:

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

Solution(javascript)

/**
 * @param {number[]} nums
 * @return {number}
 */
const longestSubarray = function (nums) {
  let prev = 0
  let current = 0
  let max = 0
  if (nums.every(x => x === 1)) {
    return nums.length - 1
  }
  for (let i = 0; i < nums.length; i++) {
    const num = nums[i]
    const next = num[i + 1]
    if (num === 1) {
      current += 1
      max = Math.max(max, prev + current)
    } else if (num === 0) {
      max = Math.max(prev + current, max)
      if (next === 0) {
        prev = 0
        current = 0
      } else {
        prev = current
        current = 0
      }
    }
  }
  return max
}