Here are some of the harder questions or the more interesting questions that I have answered.
How can you convince your colour-blind friend that two balls have the same colour?
Filling bins with pairs of balls
Finding the cheapest buy order with fixed inflation for each product
Solving recurrence relation with minimum and factorial
Primitive recursive plus Ackermann
Does this context-free grammar generate a regular language?
Minimum and maximum of sum of inverse degree of a graph
Proof of a greedy algorithm concerning “Buy and Resell Problem”
How to produce nonzero absolute differences between neighboring numbers on a circle as long as possible?
lower bound proof with adversary argument
How to solve F(n)=F(n-1)+F(n-2)+f(n) recursive function?
When is the minimum spanning tree for a graph not unique
Here are some counterexamples in my answers.
All superlinear runtime algorithms are asymptotically equivalent to convex function?
Finding the longest path in an undirected node-weighted tree
Gerrymandering Problem: Variant on Set Partitioning
Does an optimal path imply the heuristic is admissible?
Rooted Tree Isomorphism Algorithm
Local search to find minimum degree spanning tree
Steiner tree problem in graphs of diameter 3
Does every infinite context free language contain an infinite regular subset?
Is a set of acyclic |V| - 1 light edges always a Minimum Spanning Tree?