This text explains a binary algorithm to calculate a power set of any sequence. It has a sample code in C#.
Algorithms
Speeding up calculation of an average in continuous processesSpeeding up calculation of an average in continuous processes
Processing big sets of data can cause a low performance due to inefficient calculations. In order to overcome this issue we should rewrite calculations in a way which allows getting

String Expression CalculatorString Expression Calculator
Parsing of math equations from text expressions is the interesting thing. This task is close to LL parsing but can be solved in different ways. This approach tends to be the simplest