Count Occurrences of Element in Sorted Array | Lower and Upper Bound | C++ Java Python
In this video, we will solve the problem of counting the number of occurrences of an element in a sorted array using the Binary Search pattern.
Instead of scanning the entire array, we can optimize the solution by finding the first and last occurrence of the target element and calculating the count efficiently.
We will learn:
Why the brute force approach O(n) is not optimal
How to use Binary Search to reduce time complexity to O(log n)
Finding the first occurrence using lower bound concept
Finding the last occurrence using upper bound concept
How to calculate the total count using indices
Step-by-step intuition and dry run
Handling edge cases like element not present
Clean implementations in C++, Java, and Python
This problem is very important for interviews because it teaches how to extend binary search beyond simple search problems and apply it to range-based queries.
Watch till the end to master the count occurrences pattern, which is frequently asked in product-based companies.
Rising Brain (DSA Sheet):
https://www.risingbrain.org/sheet
Connect with me here:
LinkedIn – / anjalikumari22
Instagram – / rbanjali.codes
Twitter (X) – https://x.com/anjali1kumari?s=21