Master DSA Topics - February, 2026

Practice problems across 75+ categories

All Coding Problems

Practice coding problems across all companies and topics 3600 problems | 879 Easy | 1856 Medium | 842 Hard

# Problem Difficulty Topics
14 Longest Common Prefix Easy
ArrayStringTrie
15 3Sum Medium
ArrayTwo PointersSorting
16 3Sum Closest Medium
ArrayTwo PointersSorting
17 Letter Combinations of a Phone Number Medium
Hash TableStringBacktracking
18 4Sum Medium
ArrayTwo PointersSorting
19 Remove Nth Node From End of List Medium
Linked ListTwo Pointers
20 Valid Parentheses Easy
StringStack
21 Merge Two Sorted Lists Easy
Linked ListRecursion
22 Generate Parentheses Medium
StringDynamic ProgrammingBacktracking
23 Merge k Sorted Lists Hard
Linked ListDivide and ConquerHeap (Priority Queue)
24 Swap Nodes in Pairs Medium
Linked ListRecursion
25 Reverse Nodes in k-Group Hard
Linked ListRecursion
26 Remove Duplicates from Sorted Array Easy
ArrayTwo Pointers
27 Remove Element Easy
ArrayTwo Pointers
28 Find the Index of the First Occurrence in a String Easy
Two PointersStringString Matching
Showing 16-30 of 3602
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public class MyFirstJavaProgram { Edit & Run

   /* This is my first java program.
    * This will print 'Hello, World!' as the output
    */

   public static void main(String []args) {
      System.out.println("Hello, World!"); // prints
   }
}

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