Thread: finding the largest ascending subsequence..

Originally Posted by matsp

And how do you propose we solve that problem?

Of course, you can remove ALL of the prev variables, as they are just set, never referenced.

You can also remove best if you only want to find ONE max value.

--
Mats

can you propose a practical solution
??

i have done a big peace of work myself doing this base code
and i would understand how "find largest sequence" works
if i had something to learn it from

i got this base code and i dont know what to do next

Code:

#include <stdio.h>
int max_set(int arr[], int size,int index,int bef);
int main()
{
    int array[7] = {9, 1, 3,0,7,10,11};

    printf("%d\n",max_set(array,7,0,array[0]));
    return 0;
}

int max_set(int arr[], int size,int index,int bef) 
{
	int temp,bigger;
   if (index==size)
   {
     return 1;
   }
   if (arr[index]>bef)
	    {
     return 1+max_set(arr,size,index+1,arr[index]);
   }
   else
   {
     return max_set(arr,size,index+1,bef);
   }
       
}//end of function

i could write an iterative code
that solves it using external loop

do you know how to transform this code into the single function recursion??

what is the general solution
so it will be done from 1 function??

in what point in this recursive function
i can put the value that it returns into a variable??

This appears to be a similar topic.

http://cboard.cprogramming.com/showthread.php?t=108515

in what point in this recursive function i can store the
value that it returns into a cell of an array
??

it appears that there is no point in the code of this recursion where there i can
store the total result that it returns

??

i tried to insert the resolt into a cell of an array

but its not working

Code:

#include <stdio.h>
int max_set(int arr[], int size,int index,int bef);
int main()
{
    int array[7] = {9, 1, 3,0,7,10,11};
    int b[1];
	b[0]=0;
    printf("%d\n",max_set(array,7,0,array[0],b[1]));
    return 0;
}


int max_set(int arr[], int size,int index,int bef,int b[]) 
{
	int temp,bigger;
   if (index==size)
   {
     return 1;
   }
   if (arr[index]>bef)
	    {
     return 1+max_set(arr,size,index+1,arr[index],b[1]);
	 b[1]=max_set(arr,7,0,arr[0],b[1]);
   }
   else
   {
     return max_set(arr,size,index+1,bef,b[1]);
   }
       
}//end of function

i got this crude code

??

Code:

int max_set(int arr[], int size,int index,int bef,int t_set) 
{
     int temp;
	 if (index==size)
	 {
        return t_set;
	 }
	 temp=max_set(arr,size,index+1,bef,t_set)
     if(temp>t_set)
	 {
        return temp;
	 }
	 else
	 {
        return t_set;
	 }



}//end of function

but i dont know how to integrate in it
this base code
??

Code:

int max_set(int arr[], int size,int index,int bef) 
{
	int temp,bigger;
   if (index==size)
   {
     return 1;
   }
   if (arr[index]>bef)
	    {
     return 1+max_set(arr,size,index+1,arr[index]);
   }
   else
   {
     return max_set(arr,size,index+1,bef);
   }
       
}//end of function

The posted code is oversimplified in the sense that you have a mind boggling number of cases to consider before the recursive function can even return from processing a single set.

what you advise to do
in order to combine them?
and to get the largest set

Can you post the latest 'n greatest code you have currently. As stated previously each frame of a recursive function that is pushed onto the stack is a link in the chain so imo don't try to solve bits and pieces of it separately and expect them all to somehow automagically work together because that will invariably break linkages across the frames.

oh god you can't be serious

I tried to implement it and it isnt very difficult. My implementation is all recursive, exactly as you require it to be and its just 5 lines of code (not counting the head and the two braces).

I admit, I had to think about it a couple of minutes but it works with returning nothing but an int.
Anyway, I don't want to spoil the party so im just posting the function header

Code:

int max_seq(int *arr, int i, int last, int len)
{

}