WHAT IS AN ALGORITHM?

The best definition of algorithms that I have come across is the following:

Algorithms are a series of steps or rules for solving a computational problem.

A computational problem is a collection of questions that computers might be able to solve.

An example of a simple algorithm could be one used by a coffee maker, it might look something like this:

					
	if (clock.getTime() == 7am){
		coffeMaker.boilWater();
		
		if(water.isBoiled()){
			coffeMaker.addCoffee();
			coffeMaker.pourCoffee();
		}
		
	} else{
		coffeMaker.doNothing();
	}

ALGORITHM EFFICIENCY

Algorithm efficiency is the study of the amount of resources used by an algorithm. The less resources used by the algorithm the more efficient it is. Nevertheless, to have a good comparison between different algorithms we can compare based on the resources it uses: how much time it needs to complete, how much memory it uses to solve a problem or how many operations it must do in order to solve the problem

Time efficiency: a measure of amount of time an algorithm takes to solve a problem.

Space efficiency: a measure of the amount of memory an algorithm needs to solve a problem.

Complexity theory: a study of algorithm performance based on cost functions of statement counts.