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

[Henrik Bengtsson]

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 Александр Дубровский <dubrovvsskkyy using 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]]
>
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