Ahmdal’s Law
We need to bear in mind the Ahmdal’s Law when doing code optimisation. The speed up can be described in the following equation: Speedup = time_old /time_new Where, the …
Category: general
Simple C++ Coding Exercise – Use Lookup Table to Eliminate the Condition Checks
There is a popular IQ question, e.g. according to the first few number patterns, find the answer to the input: 1234 = 0 4567 = 1 2345 = 0 …
C++ Coding Example, Using Hash Algorithm to Remove Duplicate Number by O(n)
Hashing is an important technique in Computer Science. There are many cases that you can use Hash to speed up your algorithms (e.g. by reducing from O(n^2) to O(n) …
Fast Power of Two Equal or Larger than a 32-bit Integer
I have seen a naive implementation at work today (written by a colleague). My colleague intends to generate a number that is power of two, and the number is …
Using Faster Integer Power in Java
In Java Math Package, there is a pow function with returns double type. However, we can speed up this if only integer (long type) parameters are required, i.e. compute integer power …
