thr3ads.net - R help - [R] Please correct my iterative merge sort code. The lack of recursion in the code is the main condition. [Dec 2019]

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Александр Дубровский

2019-Dec-15 15:18 UTC

[R] Please correct my iterative merge sort code. The lack of recursion in the code is the main condition.

mrg <- function(A,B){
  R <- c()
  while(length(A)>0  length(B)>0){
    if(A[1]<B[1]){
      R <- c(R,A[1])
      A <- A[-1]
    } else{
      R <- c(R,B[1])
      B <- B[-1]
    }
  }
  return(c(R,A,B))
}
msort <- function(A){
  if(length(A)<2){
    return(A)
  } else{
    R <- c()
    W <- c()
    x <- 8
      for(i in 1:length(A)){
        if(i%%2==0){
      R <- c(R,mrg(A[(i-1)],A[i]))
        }
      }
     }
  if((length(A)%%2)==1){
    R <- c(R,A[length(A)])
  }
  for(i in 1:length(R)){
    if(i%%4==0){
      j <- i
      W <- c(W,mrg(R[(j-3):(j-2)],R[(j-1):j]))
    }
  }
  if((length(R)%%4)==3){
    W <- c(W,mrg(R[(j+1):(j+2)],R[(j+3)]))
  }
  if((length(R)%%4)<3 && (length(R)%%4)!=0){
    W <- c(W,R[(j+1):length(R)])
  }
  R <- W
  W <- c()
  while(x<length(R)){
    for(i in 1:length(R)){
      if(i%%x==0){
        j <- i
        W <- c(W,mrg(R[(j-(x-1)):(j-(x%/%2))],R[(j-(x%/%2)+1):j]))
      }
    }
    if((length(R)%%x)>(x%/%2)){
      W <- c(W,mrg(R[(j+1):(j+(x%/%2))],R[(j+(x%/%2)+1):length(R)]))
    }
    if((length(R)%%x)<=(x%/%2) && (length(R)%%x)!=0){
      W <- c(W,R[(j+1):length(R)])
    }
    x <- x*2
    R <- W
    W <- c()
  }
    R <- mrg(R[1:j],R[(j+1):length(R)])
  return(R)
}

	[[alternative HTML version deleted]]

Henrik Bengtsson

2019-Dec-16 16:23 UTC

head link

[R] Please correct my iterative merge sort code. The lack of recursion in the code is the main condition.

Folks on this list, this is my personal opinion, but please refrain from
answering this person's requests. It's pretty clear by now that they are
misusing your good intentions of trying to help people interested in R to
get their homework-like "questions" answered. There are no indications
that
this person has even attempted to solve the "problems" themselves.
This
smells bad intent to me.

/Henrik

On Mon, Dec 16, 2019, 07:40 ????????? ?????????? <dubrovvsskkyy at
gmail.com>
wrote:
> mrg <- function(A,B){
>   R <- c()
>   while(length(A)>0  length(B)>0){
>     if(A[1]<B[1]){
>       R <- c(R,A[1])
>       A <- A[-1]
>     } else{
>       R <- c(R,B[1])
>       B <- B[-1]
>     }
>   }
>   return(c(R,A,B))
> }
> msort <- function(A){
>   if(length(A)<2){
>     return(A)
>   } else{
>     R <- c()
>     W <- c()
>     x <- 8
>       for(i in 1:length(A)){
>         if(i%%2==0){
>       R <- c(R,mrg(A[(i-1)],A[i]))
>         }
>       }
>      }
>   if((length(A)%%2)==1){
>     R <- c(R,A[length(A)])
>   }
>   for(i in 1:length(R)){
>     if(i%%4==0){
>       j <- i
>       W <- c(W,mrg(R[(j-3):(j-2)],R[(j-1):j]))
>     }
>   }
>   if((length(R)%%4)==3){
>     W <- c(W,mrg(R[(j+1):(j+2)],R[(j+3)]))
>   }
>   if((length(R)%%4)<3 && (length(R)%%4)!=0){
>     W <- c(W,R[(j+1):length(R)])
>   }
>   R <- W
>   W <- c()
>   while(x<length(R)){
>     for(i in 1:length(R)){
>       if(i%%x==0){
>         j <- i
>         W <- c(W,mrg(R[(j-(x-1)):(j-(x%/%2))],R[(j-(x%/%2)+1):j]))
>       }
>     }
>     if((length(R)%%x)>(x%/%2)){
>       W <- c(W,mrg(R[(j+1):(j+(x%/%2))],R[(j+(x%/%2)+1):length(R)]))
>     }
>     if((length(R)%%x)<=(x%/%2) && (length(R)%%x)!=0){
>       W <- c(W,R[(j+1):length(R)])
>     }
>     x <- x*2
>     R <- W
>     W <- c()
>   }
>     R <- mrg(R[1:j],R[(j+1):length(R)])
>   return(R)
> }
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
	[[alternative HTML version deleted]]

Jeff Newmiller

2019-Dec-16 22:19 UTC

head link

[R] Please correct my iterative merge sort code. The lack of recursion in the code is the main condition.

The Posting Guide is pretty clear about "no homework" (it is also
clear that this is a plain text mailing list). I think the recent replies to the
OP have been clear on how this should be approached. I don't know what the
OP "intends", but isolated (not replies to the original message)
emails that have only code and no question in them are certainly not appropriate
in this list.

"dubrovvsskkyy", please adhere to the Posting Guide in future posts.
If you are_not_ asking for homework help then please explain why you are
ignoring the advice given in previous posts.

On December 16, 2019 8:23:46 AM PST, Henrik Bengtsson <henrik.bengtsson at
gmail.com> wrote:>Folks on this list, this is my personal opinion, but please refrain
>from
>answering this person's requests. It's pretty clear by now that they
>are
>misusing your good intentions of trying to help people interested in R
>to
>get their homework-like "questions" answered. There are no
indications
>that
>this person has even attempted to solve the "problems" themselves.
This
>smells bad intent to me.
>
>/Henrik
>
>On Mon, Dec 16, 2019, 07:40 ????????? ??????????
><dubrovvsskkyy at gmail.com>
>wrote:
>
>> mrg <- function(A,B){
>>   R <- c()
>>   while(length(A)>0  length(B)>0){
>>     if(A[1]<B[1]){
>>       R <- c(R,A[1])
>>       A <- A[-1]
>>     } else{
>>       R <- c(R,B[1])
>>       B <- B[-1]
>>     }
>>   }
>>   return(c(R,A,B))
>> }
>> msort <- function(A){
>>   if(length(A)<2){
>>     return(A)
>>   } else{
>>     R <- c()
>>     W <- c()
>>     x <- 8
>>       for(i in 1:length(A)){
>>         if(i%%2==0){
>>       R <- c(R,mrg(A[(i-1)],A[i]))
>>         }
>>       }
>>      }
>>   if((length(A)%%2)==1){
>>     R <- c(R,A[length(A)])
>>   }
>>   for(i in 1:length(R)){
>>     if(i%%4==0){
>>       j <- i
>>       W <- c(W,mrg(R[(j-3):(j-2)],R[(j-1):j]))
>>     }
>>   }
>>   if((length(R)%%4)==3){
>>     W <- c(W,mrg(R[(j+1):(j+2)],R[(j+3)]))
>>   }
>>   if((length(R)%%4)<3 && (length(R)%%4)!=0){
>>     W <- c(W,R[(j+1):length(R)])
>>   }
>>   R <- W
>>   W <- c()
>>   while(x<length(R)){
>>     for(i in 1:length(R)){
>>       if(i%%x==0){
>>         j <- i
>>         W <- c(W,mrg(R[(j-(x-1)):(j-(x%/%2))],R[(j-(x%/%2)+1):j]))
>>       }
>>     }
>>     if((length(R)%%x)>(x%/%2)){
>>       W <- c(W,mrg(R[(j+1):(j+(x%/%2))],R[(j+(x%/%2)+1):length(R)]))
>>     }
>>     if((length(R)%%x)<=(x%/%2) && (length(R)%%x)!=0){
>>       W <- c(W,R[(j+1):length(R)])
>>     }
>>     x <- x*2
>>     R <- W
>>     W <- c()
>>   }
>>     R <- mrg(R[1:j],R[(j+1):length(R)])
>>   return(R)
>> }
>>
>>         [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
>	[[alternative HTML version deleted]]
>
>______________________________________________
>R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.
-- 
Sent from my phone. Please excuse my brevity.

R help - Dec 2019 - Please correct my iterative merge sort code. The lack of recursion in the code is the main condition.

[R] Please correct my iterative merge sort code. The lack of recursion in the code is the main condition.

[R] Please correct my iterative merge sort code. The lack of recursion in the code is the main condition.

[R] Please correct my iterative merge sort code. The lack of recursion in the code is the main condition.