Summary Ranges
The problem asks to generate the smallest sorted list of ranges that cover all the numbers in the array exactly. Here’s how we can approach this:
 Initialize an empty result list.
 Iterate through the array, checking for consecutive numbers.
 If consecutive numbers are found, record the start and end of the range.
 Add the range to the result list in the desired format.
Below is the code:


This code checks for consecutive numbers and constructs the ranges accordingly, making sure to handle the case when a range consists of only a single number. It returns the desired list of ranges for the given sorted unique integer array nums
.


Problem Classification
Array Manipulation: The problem involves dealing with an array of integers and performing operations on it.
Range Extraction: The primary task is to identify and extract the ranges of consecutive numbers.
Formatting and Representation: The ranges identified need to be represented and formatted in a specific string format.
Sequential Data Processing: The problem involves a sequential scanning process of the given data (array).
Language Agnostic Coding Drills
Here’s how you can break down the concepts in this problem:
Arrays/Lists: Understanding how to iterate through a list or array, the concept of index, and using array length.
Loops and Conditions: Understand how to use while loops and nested ifelse conditions.
String Manipulation: Understand how to convert an integer to a string and how to concatenate strings.
Working with multiple variables and pointers: This problem requires keeping track of two pointers (
start
andend
) simultaneously.
Now, let’s break down the problemsolving approach:
Initialize variables: Start by initializing two pointers at the beginning of the list,
start
andend
, along with an empty result list.Iterate over the list: Start a while loop which continues till both
start
andend
are less than the length of the input list.Find a range: Inside the loop, check if
end + 1
is still within the array bounds and if the next number is a continuation of the current sequence (nums[end] + 1 == nums[end + 1]
). If so, incrementend
. This will extend the current range.Handle end of range or sequence: If the next number isn’t a continuation of the current sequence, we’ve found the end of a range. Check if
start
andend
are pointing to the same number. If so, append it to the result as a string. If not, append the range (fromstart
toend
) as a string to the result.Move to next range: After appending to the result, move the
start
andend
pointers appropriately to start tracking the next range.Final result: Return the result list which contains all the ranges in string format.
The problem can then be solved by integrating these concepts and following the problemsolving approach.
Targeted Drills in Python
 Working with Arrays/Lists:


 Loops and Conditions:


 String Manipulation:


 Working with multiple variables and pointers:


The final solution can then be created by integrating all these concepts:


This code will correctly identify and format all consecutive ranges in the input array.