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Problems Contests

Practice coding problems

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Practice coding problems

Data structures and algorithms problems in Python and Java. Read any problem for free; sign in to run and submit your code.

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18 problems

ProblemDifficultyTopicsTime

Power Function (Fast Exponentiation)
Medium15 min
- Recursion Fundamentals

Nth Fibonacci NumberFoundationalMedium15 min

DP Foundations

Climbing Stairs - Count Distinct WaysMedium15 min

DP Foundations

Longest Consecutive SequenceMedium20 min

Hash Tables

Product of Array Except SelfMedium20 min

Prefix Sums and Difference Arrays

Subarray Sum Equals KMedium20 min

Prefix Sums and Difference Arrays

3SumMedium20 min

Two Pointers

Next PermutationMedium20 min

Subsets, Permutations and Combinations

Minimum Size Subarray SumMedium20 min

Sliding Window

Find All Duplicates in an ArrayMedium20 min

Array Techniques

Sort ColorsMedium20 min

Sorting Algorithms

Rotate ArrayMedium20 min

Array Techniques

Container With Most WaterMedium20 min

Two Pointers

Maximum SubarrayMedium20 min

Dynamic Programming

Merge IntervalsMedium20 min

Scheduling and Intervals

Find the Duplicate NumberMedium20 min

Count Pairs With a Given SumFoundationalMedium25 min

Hash-Based Techniques

Find the Number That Appears OnceFoundationalMedium25 min

Bit Manipulation

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