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Message:

lists of lists and recursion

Posted by SC on June 23, 2001 at 11:13 AM

hi all
i have a problem in recursion. I was given the following info:

class abstract Plan
{
....
public String name()
public abstract int howLong()//time needed to finish
// the plan
}

/** the simplePlan is a single task, which has a name indicating what must be done, and a duration indicating how long it will take. We can build larger plans from existing ones in two ways: swequentially or concurrently.
*/
class SimpleTask extends Plan
{
int _duration;
......
int howLong()
{
return _duration; //This line is my answer
}
}

/** the sub-plans must be done one after the other
so the total time taken is the sum */
class SequentialPlan extends Plan
{
LinkedList _pieces; //holds Plan objects

int howLong()
{
// define
}

/** the sub-plans all start together,
so the total time taken is the maximum time*/
class SequentialPlan extends Plan
{
LinkedList _pieces;

int howLong()
{
// define
}
}

for example, sub-plan "class" has one task: "design 4" (means 4 days), after we finish the design, we need to do the coding: which has two concurrent sub-plans: account and main.
Under account, we need to do the following step by step: interface 1, code 5, test 2.
Under main, we need to do the following step by step:
interface 1, code 4, test 1.
so for this sub-plan "class", the time needed is: 12, which consists of 4 days from design and the longer of coding from account, 8.
We are required to define the howLong() method. for each of the three child classes.

can anyone give me a hint to start???
I've tried lots of ways, but seems something is missing all the time. Really appreciate any help.

Best regards,
SC