Question

Use R:There is a numeric vector of integers; every element appears twice except for one Implement the function findUnique() to find the element that appears only once in the numeric vector using loop. Implement the function findUnique2() to find the element that appears only once in the numeric vector without using loop. datavec <- c(3, 5, 2, 7, 7, 13, 13, 2, 8, 1, 3, 1, 5) sample output is 8

A <- function(s){

for(x in 1:length(s)){

    found <- FALSE

    for(j in 1:length(s)){

      if(x!=j){

        if(s[x]==s[j]){

          found <- TRUE

          break

        }

      }

    }

    if(!found){

      return(s[x])

    }

}

}

Answer 1

CODE:

findUnique <- function(s){
#take each element and compare with other and check found or not
for(x in 1:length(s)){
#intially found is false
found <- FALSE
for(j in 1:length(s)){
if(x!=j){
if(s[x]==s[j]){
#when element occuers found will became true
found <- TRUE
break
}
}
}
#if not found that means no second occurence.
if(!found){
return(s[x])
#return the value
}
}
}

#finding element using recursion
findUnique2<- function(s,pos){
#find all occurences of element
ind=which(s[pos] == s)
#if element occur 1 time then return it
if(length(ind)==1){
return(s[pos])
}
#if element occur 2 time then shift to next element
pos=pos+1
findUnique2(s,pos)
}

#take a vector
datavec <- c(3, 5, 2, 7, 7, 13, 13, 2, 8, 1, 3, 1, 5)
#pass vector to findUnique() to find the element using loops.
print(findUnique(datavec))
#pass vector to findUnique2() to find the element without using loops.
print(findUnique2(datavec,1))

OUTPUT:

8

8