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CC#

•Created by vl4do on 7/31/2024 in #help

✅ Fibonacci sequence

honestly I'm not sure

33 replies

CC#

•Created by vl4do on 7/31/2024 in #help

✅ Fibonacci sequence

i just did NOT think of it

33 replies

CC#

•Created by vl4do on 7/31/2024 in #help

✅ Fibonacci sequence

great question, a for-loop is better

33 replies

CC#

•Created by vl4do on 7/31/2024 in #help

✅ Fibonacci sequence

yeah why didn't i

33 replies

CC#

•Created by vl4do on 7/31/2024 in #help

✅ Fibonacci sequence

actually

33 replies

CC#

•Created by vl4do on 7/31/2024 in #help

✅ Fibonacci sequence

33 replies

CC#

•Created by vl4do on 7/31/2024 in #help

✅ Fibonacci sequence

and continue

33 replies

CC#

•Created by vl4do on 7/31/2024 in #help

✅ Fibonacci sequence

next number 0 + 1

33 replies

CC#

•Created by vl4do on 7/31/2024 in #help

✅ Fibonacci sequence

then it starts

33 replies

CC#

•Created by vl4do on 7/31/2024 in #help

✅ Fibonacci sequence

it's 0, 1 as the first two numbers

33 replies

CC#

•Created by vl4do on 7/31/2024 in #help

✅ Fibonacci sequence

yeah i could have made the array outside the method and put it as a class field. That is actually my preferred way to do stuff like this cus it makes it clearer for me

33 replies

CC#

•Created by vl4do on 7/31/2024 in #help

✅ Fibonacci sequence

that's how it is done bottom-up

33 replies

CC#

•Created by vl4do on 7/31/2024 in #help

✅ Fibonacci sequence

okay it is <

33 replies

CC#

•Created by vl4do on 7/31/2024 in #help

✅ Fibonacci sequence

it may be <= instead of < but i am not on vscode and im too stupid to do it in my head

33 replies

CC#

•Created by vl4do on 7/31/2024 in #help

✅ Fibonacci sequence

public int FibButBottomUp(int nth_number)
{
     if(nth_number == 0) return 0;
     if(nth_number == 1) return 1;


     int first_num = 0, second_num = 1;
     int count = 2;

     while(count < nth_number)
     {
          int temp = first_num + second_num; //getting the next number
          first_num = second_num;        
          second_num = temp;

          count++;
     }

     return second_num;
}

public int FibButBottomUp(int nth_number)
{
     if(nth_number == 0) return 0;
     if(nth_number == 1) return 1;


     int first_num = 0, second_num = 1;
     int count = 2;

     while(count < nth_number)
     {
          int temp = first_num + second_num; //getting the next number
          first_num = second_num;        
          second_num = temp;

          count++;
     }

     return second_num;
}

33 replies

CC#

•Created by vl4do on 7/31/2024 in #help

✅ Fibonacci sequence

like with a loop

33 replies

CC#

•Created by vl4do on 7/31/2024 in #help

✅ Fibonacci sequence

i think this is also top-down approach...i am not 100% sure but that should be the term, for bottom-up approach instead of doing recusively + using caching you'd just do it completely iteratively

33 replies

CC#

•Created by vl4do on 7/31/2024 in #help

✅ Fibonacci sequence

while the first code snippet is right(and even sorta optimal)...that's a pretty bad way to explain the point of memoization Memoization exists for situations where there is redundant calculations being done. for example here,

public int Fib(int nth_number)
{
     if(nth_number == 0) return 0;
     if(nt_number == 1) return 1;

     return Fib(nth_number - 1) + Fib(nth_number - 2); 
}

public int Fib(int nth_number)
{
     if(nth_number == 0) return 0;
     if(nt_number == 1) return 1;

     return Fib(nth_number - 1) + Fib(nth_number - 2); 
}

If i used nth_number as something like 5, it'd start off as a call to Fib(5), then Fib(5) calls (case a)Fib(4) and Fib(3) for case a: Fib(4) calls Fib(3) and Fib(2) Fib(3) calls Fib(2) and Fib(1), then Fib(2) calls Fib(1) and Fib(0) --ends here Fib(2) (from the Fib(4) call) is done again (an example of a redundant call as Fib(2) was already done) for something like Fibonacci it wouldn't matter too much to have redundant calls, but for situations similar in nature to it with stuff like expensive calculations in each function call, it pays to have redundant calls. That's where memoization comes in, it caches(stores) each call once completed so that if this call were to happen again it would not need to do the expensive calculations again, it just returns the cached call. A way to properly implement memoization in Fibonacci would be

public int Fib(int nth_number)
{
     //all the elements in the array are 0
     int[] memo = new int[nth_number];
     memo[0] = 0;                       //first number is always zero
     memo[1] = 1;                       //second number is always one

     //im assuming nth_number is never negative
     if(nth_number < 2) return memo[nth_number];
     
     return Helper(nth_number, memo):
}

private int Helper(int n, int[] memo)
{    
     if(memo[n] != 0) return memo[n];
     else{
         memo[n] = Helper(n - 1, memo) + Helper(n - 2, memo);
         return memo[n];
     }    
}

public int Fib(int nth_number)
{
     //all the elements in the array are 0
     int[] memo = new int[nth_number];
     memo[0] = 0;                       //first number is always zero
     memo[1] = 1;                       //second number is always one

     //im assuming nth_number is never negative
     if(nth_number < 2) return memo[nth_number];
     
     return Helper(nth_number, memo):
}

private int Helper(int n, int[] memo)
{    
     if(memo[n] != 0) return memo[n];
     else{
         memo[n] = Helper(n - 1, memo) + Helper(n - 2, memo);
         return memo[n];
     }    
}

33 replies

CC#

•Created by engineertdog on 7/31/2024 in #help

Parallel list

there is also https://learn.microsoft.com/en-us/dotnet/api/system.threading.tasks.parallel.foreachasync?view=net-8.0

4 replies

CC#

•Created by engineertdog on 7/31/2024 in #help

Parallel list

Task.WhenAll is fine yeah(btw unless I'm blind TransformRecordsParallel is never called in your code)

4 replies

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