Reverse the order of nodes in a singly linked list.
Given an original singly linked list A->B->C->D
graph TD;
A-->B;
B-->C;
C-->D;
Reverse it to D->C->B->A;
graph TD;
D-->C;
C-->B;
B-->A;
This coding exercise is very popular among employers. Personally, when actively looking for my next project, I get asked this question, at least, once a week. Keep a solution to this, or a similar coding exercise, in your tool belt.