1493 Longest Subarray of 1’s After Deleting One Element 1

Joel Castillo Espinosa 2

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.

Examples

  • 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.

SOLUTION 3

long_sub <- function(nums){
  max_val <- 0 # the default value
  
  # in each iteration, drop i-element and get the 
    # length of the longest subarray of 1s
  for (i in 1:length(nums)) {
    nums_alt <- nums[-i]
    
    # create vector where i-element is 0 
    vector_1 <- c(0)  
    for (i in 1:length(nums_alt)) {
      if (nums_alt[i] == 0) {
        vector_1 <- c(vector_1, i) }
    }
    vector_1 <- c(vector_1, length(nums_alt) + 1)
    
    # auxiliary vector to count the subarrays
    count_1 <- c()
    
    for (i in 2:length(vector_1)) {
      count_1[i -1] <- vector_1[i] - vector_1[i - 1] - 1
    }
    
    # Get the length of the longest subarray of 1s
    max_count <- max(count_1) 
    
    # compare to get the maximum
    max_val <- ifelse(max_val > max_count, max_val, max_count)
  }
  return(max_val)
}

Examples using the function

We can use the examples presented before.

long_sub(nums = c(1,1,0,1))

## [1] 3

long_sub(nums = c(0,1,1,1,0,1,1,0,1))

## [1] 5

long_sub(nums = c(1,1,1))

## [1] 2

  1. This problem is originally from LeetCode, you can find it in Leetcode. ↩

  2. Email: jocastillo@colmex.mx. For more content visit my website: https://joelcastillo.netlify.app
    If you have any questions or suggestions, I’d be grateful to hear from you. ↩

  3. This solution is entirely my own work. It was developed using R version 4.4.1 (2024-06-14 ucrt). ↩