Summary Ranges

Problem Description

You are given a sorted unique integer array nums. A range [a,b] is the set of all integers from a to b (inclusive). Return the smallest sorted list of ranges that cover all the numbers in the array exactly. Each range [a,b] in the list should be output as:

• "a->b" if a != b
• "a" if a == b

Key Insights

• The input array is sorted and contains unique integers, which simplifies the identification of ranges.
• A range starts when the current number is not consecutive to the previous number.
• The end of a range is marked when the next number is not immediately after the last number in the current range.

Space and Time Complexity

Time Complexity: O(n), where n is the number of elements in the input array since we traverse through the array once.
Space Complexity: O(1) for the range list storage, ignoring the output space.

Solution

To solve the problem, we can use a simple iteration approach:

1. Initialize an empty list to store the ranges.
2. Use a loop to iterate through the sorted array:
   • Identify the start of a new range when the current number is not consecutive to the last.
   • Continue until the end of the range is reached, then store it in the required format.
3. Handle the edge case where the input array might be empty.

Code Solutions