What does “in constant time” imply?

Question

I work as a programmer, but have no computer science background, so recently I\'ve been following along with the excellent MIT OpenCourseWare intro to Computer Science and Progr

Answer 1

Constant time here means not dependent on number of inputs (not the input itself), and if you aren't allowed for or goto, the only way to make it depend on the number of inputs is by conditionals and recursion. Although you could argue that recursion isn't necessary with some debatable solutions. Eg. (in C)

if(ReadInput()) DoSomeThing();
if(ReadInput()) DoSomeThing();
if(ReadInput()) DoSomeThing();
if(ReadInput()) DoSomeThing();