Practice/Meta/Leetcode 163. Missing Ranges

Leetcode 163. Missing Ranges

CodingMust

Problem

You are given a sorted array of unique integers nums and two integers lower and upper that define an inclusive range. Your task is to identify all numbers and continuous ranges that fall within [lower, upper] but are missing from the array.

Return a list of strings where each string represents either:

• A single missing number formatted as "x"
• A continuous range of missing numbers formatted as "a->b"

The returned list should be in ascending order.

Requirements

1. The input array nums is sorted in ascending order and contains distinct integers
2. Return each missing value or range within the bounds [lower, upper]
3. Format single missing numbers as a plain string (e.g., "5")
4. Format ranges of two or more consecutive missing numbers as "start->end" (e.g., "10->15")
5. Return an empty list if no numbers are missing

Constraints

• 0 ≤ nums.length ≤ 10^5
• -10^9 ≤ lower ≤ upper ≤ 10^9
• All values in nums are distinct
• nums is sorted in ascending order
• -10^9 ≤ nums[i] ≤ 10^9

Examples

Example 1:

` Input: nums = [0, 1, 3, 50, 75], lower = 0, upper = 99 Output: ["2", "4->49", "51->74", "76->99"] Explanation:

• 2 is a single missing number
• 4 through 49 is a missing range
• 51 through 74 is a missing range
• 76 through 99 is a missing range `

Example 2:

Input: nums = [], lower = 1, upper = 1 Output: ["1"] Explanation: The entire range contains just one number and it's missing

Example 3:

Input: nums = [1, 2, 3, 4, 5], lower = 1, upper = 5 Output: [] Explanation: All numbers in the range are present

Example 4:

Input: nums = [10, 20], lower = 5, upper = 25 Output: ["5->9", "11->19", "21->25"] Explanation: Missing ranges appear before, between, and after the array elements