The first tripod stick in the world! No need to handheld. Just remove the tripod, and it becomes a normal handheld selfie stick! Fits most smartphones in variety angles! Safe, Stable. Compatible with most iOS and Android smartphones. You can use it as a phone stand, and just put it there to watch videos, facetime and have fun with friends! Record your amazing journey and daily life! Put it on the desk to take selfies.

Finding sub-arrays that sum up to zero. By zzurang on June 29, 2011. Here is working ruby implementation. There is a linear time solution for this. But this is more intuitive solution as it extends permutation of sub-array. Using proper memoization help the process prune a lot.