Revquix 150

Revquix 150 is a curated list of 150 DSA problems that cover every core topic, from arrays to dynamic programming, in five languages.

It is a stronger second pass: the 80 essential problems plus 70 more that deepen every topic, so each pattern is practised more than once. Every problem is judged against hidden test cases in Python, C++, Java, JavaScript and TypeScript, and each section runs from easy to hard. Revquix 150 includes every problem in Revquix 80.

What you will practise:

• Arrays, Strings and Hashing: 19 problems such as Pair That Hits the Target, Stretches Summing to K and Median Is K.
• Two Pointers and Sliding Window: 13 problems such as Best Window Total, Three-Flag Sort and Kth Smallest Gap.
• Sorting, Binary Search and Intervals: 15 problems such as Clash-Free Calendar, First and Last Seen and Leftmost Lit Column.
• Linked Lists: 11 problems such as Turn the Chain Around, Cut Nth From End and Least Used Cache.
• Stacks and Queues: 11 problems such as Bracket Balance, Wait for Warmth and Formula Atom Counter.
• Trees and Binary Search Trees: 20 problems such as Tree Depth, Shared Ancestor and Height After Cutting.
• Heaps and Greedy: 11 problems such as Even Splits, Keep Twins Apart and Hire K for Less.
• Recursion and Backtracking: 9 problems such as Recursive Reverse, Reusable Coins to Target and Fewest Bracket Fixes.
• Graphs: 15 problems such as Island Coastline, Course Plan Feasible and Weight-Limited Paths.
• Dynamic Programming: 20 problems such as Triangle of Sums, Fewest Coins and Changing Letters Path.
• Tries, Bit Manipulation and Design: 6 problems such as The Lone Sock, Bit Distance and Dotted Word Finder.

Work through one section at a time and finish a section before you move on. If a problem feels too hard, try an easier one from the same section first, then come back to it. Every problem comes with worked examples and clear constraints.