Frequently asked DSA questions in interviews for freshers focus on arrays, strings, and fundamental trees for quick problem-solving evaluations. Mastery requires efficient time/space complexity as well as clean coding practices.

Fundamentals of Arrays

• Find a pair with a specified sum (using two pointers or a hash map).

• Maximum subarray sum (Kadane's algorithm).

• Best time to buy or sell stock (basic concepts of dynamic programming).

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Classics of Strings and Stacks

• Reverse a string or check for palindromes (using two pointers).

• Validating parentheses (using a stack).

• Finding the next greater element (monotonic stack).

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Essential Knowledge of Trees and Sorting

• Inorder/preorder traversals of binary trees (recursion).

• Merging intervals or sorting 0s, 1s, and 2s (Dutch national flag problem).

• Searching in a rotated sorted array (variant of binary search)

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