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

Александр Дубровский dubrovv@@kkyy @end|ng |rom gm@||@com
Sun Dec 15 16:18:09 CET 2019

```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)
}

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```