Coding Interview Problems

791. Custom Sort String

The Custom Sort String problem is a classic coding interview question because it tests whether you can follow a custom ordering rule...

Problem

767. Reorganize String

The Reorganize String problem is a common interview question that tests how well you handle greedy construction under strict constraints....

Problem

529. Minesweeper

Minesweeper is a deceptively rich problem. On the surface, it looks like a grid manipulation task. In reality, it tests...

Problem

540. Single Element in a Sorted Array

This problem looks simple at first glance, but it is a classic example of how problem constraints fundamentally change the...

Problem

504. Base 7

At first glance, Base 7 looks like a trivial number conversion task. In interviews, however, it is often used to assess whether...

Problem

2081. Sum of k-Mirror Numbers

This problem shows up in interview settings because it’s a compact way to test multiple “core” skills at once. You...

Problem

42. Trapping Rain Water

Trapping Rain Water, is one of the most famous Hard coding problems in the coding interview prep world. It is...

Problem

217. Contains Duplicate

Detecting duplicates in an array is a fundamental problem that appears frequently in technical interviews at companies like Google, Amazon,...

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58. Length of Last Word

String manipulation problems like "Length of Last Word" are frequently asked in interviews at companies like Google, Amazon, and Microsoft...

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288. Unique Word Abbreviation

This is a common hashing interview problem because it tests whether we can precompute a hashed lookup once and then...

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417. Pacific Atlantic Water Flow

Pacific Atlantic Water Flow is a common interview-style matrix question frequently asked by MAANG companies (Meta, Microsoft, Google, Amazon, etc.)....

Problem

56. Merge Intervals

The Merge Intervals problem is a classic introduction to the Intervals pattern. It is a favorite in interviews because it...