Assumptions: You already have taken a basic DSA course
Doing Leetcode and improving your DSA skills can be achieved with proper time management and sincere effort in 3 months. If you already have good projects and a decent CGPA in your resume, then you can get a good internship. To follow this study plan, you will only need to dedicate 1-2 hours per day.

1. First 3 weeks: Do as many easy questions as possible in the language you are comfortable with, or in a new language. So, in 21 days you can cover 100 easy questions pretty easily. This means just 5 questions per day, or even if you start slow, you will still be able to cover this number.
2. Now, start with medium questions on Leetcode. I suggest this order:
   1. Hashtable - 6 to 7 questions
   2. Linked List - 9 - 10 questions which are very common
   3. Binary Search - 9 - 10 questions
   4. Merge Sort and sorting based array questions : 9 - 10 questions
   5. Two Pointers - 7 - 8 questions
   6. Recursion and Dynamic Programming most accepted questions: These questions follow very typical patterns. So if you do these, you will understand how recursion works and will start developing logical intuitions in functional programming. - 7 -8 questions
   7. Tree questions: Each question is a code of maximum 8 lines. If you do even 10 questions, and even if you look at discuss section to understand the code, as long as you get the concept and visualisation of how the solution works, your understanding in recursion will increase significantly - 10 - 15 questions
   8. Stacks and queues questions - 10 - 15 questions
   9. Priority Queue/Heap questions - 10 - 15 questions
   10. Graph questions - 20 questions
   11. Segment Trees - 7 - 8 questions

Every topic you do, try implementing it from scratch. Because this is asked by companies and is important for one's understanding.

You can also use Leethub extension to save all your solutions of leetcode in github .

Once you are done with medium + easy questions if you have time left, then try doing hard questions which are very common and asked by companies in past years.

So, 3 weeks easy (maximum 100 - 110 questions might take even lesser time) + 11 weeks medium + past year questions

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