Question

Having trouble with writing a function in racket that would be able to use substitution like so:

Input: two atoms and a list that might itself contain lists as elements. Substitute will replace every occurrence of the first atom with the second in the list.
Example:
(substitute ‘yim ‘yam ‘(a b yim (c d yim e) (f (g h (i yim)) j))
Should return
(a b yam (c d yam e) (f (g h (i yam)) j))

Answer 1

You have to consider a linked list kind of approach. We have to create a node that has two arrays. The first array is the array of nodes. The second array is the array of atoms/elements (here strings).

class Node{
public:
vector<Node*> arr;
vector<string> atoms;
};

//Here src is yim and dest is yam

void solve(Node * head, string src, string dest){
for(int i=0;i<head->arr.size();i++){
solve(arr[i], src, dest);
}
for(int i=0;i<head->atoms.size();i++){
if(atoms[i] == a){
atoms[i] = b;
}
}
}