I am an IT project manager at an administration, and worked as software engineer before.

Here are some of the answers I found most useful or fun (not necessarily accepted, nor highest voted):

• Algorithm - Fastest way to sort an array only using these blackbox functions?
• Algorithm - Minimum number of steps to reduce number to 1
• Algorithm - Solve a maze with n balls
• Algorithm - Optimise finding time-based events
• Algorithm - Fastest way to check if a number is a vampire number?
• PHP - How to get innerHTML of DOMNode?
• PHP - How to create a pagination bar with "..." fillers
• MySql - How to create a hierarchical recursive query?
• JavaScript - Promise resolved earlier with p.then(resolve) than with resolve(p)
• JavaScript - Are ES6 template literals safer than eval?
• JavaScript - filter() for Objects
• JavaScript - Sort version-dotted number strings
• JavaScript - Calculate arithmetic expression w/o eval
• JavaScript - How to version control objects