Programming challenges

A collection of interesting questions or challenges encountered on programming interviews.

Problematic list

• Aesthetic tree cutting
• PIN variations
• Unusual walk

F.A.Q.

• Q & A

Closing thoughts

During an interview there is very little time to find and implement an optimal solution, so I am more interested in how the candidate approaches a difficult (maybe impossible) task and here's how you can gain some points:

• first, identify what kind of problem is it: path finding, sorting, merging, exploring, computation
  • maybe this problem can be solved with classical algorithms, explain which one and how it works?
• break down the big problem into smaller / simpler parts (remember "divide et impera" ?)
  • if the problem is apparently overwhelming, propose a simpler alternative version which you can solve
• classify your solution time complexity
  • if your solution is not optimal, describe how the optimal should look like
• if you have time, offer another solution (even if is less efficient)
  • here's the funniest example I have ever seen for sorting a list

    def is_sorted(a):
        return all([a[i] <= a[i+1] for i in range(len(a)-1)])
  
    while not is_sorted(a):
        shuffle(a)