Algorithms step by step
The AlgoPath blog has 6 articles in “Algorithms step by step”, newest first, written for developers without a CS degree.
The frequency map pattern
A frequency map stores each value with the number of times it appears. One pass builds it, and four common problems fall out.
2026-11-03
How does a hash table work
A hash table turns a key into an array index, and that one step explains every rule you were told to follow. Constant time is an average.
2026-10-27
Set vs map vs array: which one to use
Pick the container from the question you ask most often. Four questions, the cost table, and the cases where an array still wins.
2026-10-20
Time complexity from the constraints
The line with the input size usually decides which algorithm you are allowed. A table you can memorise in five minutes, and what to do when nobody gives you one.
2026-10-13
Big O notation explained simply
Big O answers one question: if the input doubles, what happens to the work? Five shapes, and how to read them off your own loops.
2026-10-06
Why are algorithms so hard when you can already code
Knowing a language and solving algorithm problems are two different skills. Five specific things sit between them, and none of them is talent.
2026-09-29