LEETCODE 163:FRONT MID REAR PATTERN:Efficiently Finding Missing Ranges in Sorted Integer Array

Welcome to our comprehensive tutorial on solving LeetCode Problem 163: Missing Ranges! This video will guide you through understanding the problem, developing an efficient solution, and implementing it step-by-step.
Introduction:
In this video, we'll tackle a common interview problem, "Missing Ranges." This problem is frequently asked by top tech companies and tests your ability to work with arrays and ranges. Our goal is to find the missing ranges in a sorted integer array, given a lower and upper bound.
Problem Statement:
Given a sorted integer array nums where the range of elements is in the inclusive range [lower, upper], return its missing ranges. A range [a, b] is missing if no number in nums is in the range [a, b].
Example:
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Input: nums = [0, 1, 3, 50, 75], lower = 0, upper = 99
Output: ["2", "4-49", "51-74", "76-99"]
In this example, the ranges 2, 4 to 49, 51 to 74, and 76 to 99 are missing from the array.
Approach:
Initialization: Start by initializing your results list and setting the current number to the lower bound.
Iterate Through the Array: Loop through the array and compare each element with the expected current number. If there's a gap between the current number and the array element, it means we found a missing range.
Handle Missing Ranges: Add the missing ranges to the result list. Adjust the current number accordingly.
Final Range: After iterating through the array, check if there's a missing range between the last element and the upper bound.
Edge Cases: Handle edge cases such as an empty array, a single element array, or arrays where no numbers are missing.
Step-by-Step Solution:
Initialize: Set up your variables and start from the lower bound.
Loop and Compare: Iterate through the nums array.
Add Missing Ranges: Whenever you find a missing range, add it to your result list.
Check Upper Bound: Ensure that any range between the last element and the upper bound is also considered.
Return the Result: Finally, return the list of missing ranges.
Explanation:
We start by setting our current number to the lower bound. As we iterate through the sorted array, we compare each number with our current number. If there's a gap, we identify it as a missing range. Depending on the size of the gap, we format the range accordingly (either a single number or a range of numbers).
After processing all elements in the array, we check if there's a missing range between the last element and the upper bound. This ensures we account for any gaps at the end of the range.
This approach efficiently identifies missing ranges in a single pass through the array, making it optimal for large inputs.
Why This Solution Works:
Efficiency: The solution runs in O(n) time complexity, where n is the length of the array. This ensures it can handle large inputs efficiently.
Simplicity: The logic is straightforward, making it easy to understand and implement.
Edge Case Handling: The solution gracefully handles edge cases, ensuring it works correctly for various input scenarios.
Conclusion:
By the end of this tutorial, you'll have a thorough understanding of how to solve the Missing Ranges problem on LeetCode. This solution not only prepares you for coding interviews but also enhances your problem-solving skills with arrays and ranges.
Additional Tips:
Practice: Try solving similar problems to strengthen your understanding.
Optimize: Always think about how you can optimize your solution further.
Review: Go through the code and explanation multiple times to ensure you fully grasp the concepts.
We hope this tutorial helps you in your coding journey. Don't forget to like, subscribe, and hit the notification bell to stay updated with more such videos. Happy coding!
Tags: #LeetCode #CodingInterview #MissingRanges #Programming #TechInterview #CodingChallenge #DataStructures #Algorithms
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