Minimum distance between two given nodes of a Binary Tree

PROBLEM :

Given a binary tree and two node values your task is to find the minimum distance between them.
Example :

Input:
The task is to complete the fuction findDist which takes 3 argument, the  root of the  Binary Tree and two node values a and b .
There are multiple test cases. For each test case, this method will be called individually.

Output:
The function should return min distance between two node values .

Constraints:
1 <=T<= 30
1 <=Number of nodes<= 100
1 <=Data of a node<= 1000

Example:
Input
1
2
1 2 L 1 3 R
2 3

Output
2

In above example there is one  test case which represent a tree with 3 nodes and 2 edges where root is 1, left child of 1 is 2 and right child of 1 is 3.

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SIMPLE c++ IMPLEMENTATION :
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/* A binary tree node
struct Node
{
    int data;
    struct Node* left, * right;
}; */

/* Should return minimum distance between a and b
   in a tree with given root*/
 
Node * LCA(Node*  ,int  ,int  ) ;
int distance(Node *,int,int ) ;
 
int findDist(Node* root, int a, int b)
{
    if(root==NULL)
        return 0 ;
       
    Node *ROOT ;
    ROOT=LCA(root,a,b) ;
   
    int l1,l2 ;
    l1=distance(ROOT->left,a,b) ;
    l2=distance(ROOT->right,a,b) ;
   
    return l1+l2 ;
}

Node * LCA(Node* root ,int n1 ,int n2 )
{
    if(root==NULL)
        return root ;
       
    if(root->data==n1)
        return root ;
    if(root->data==n2)
        return root ;
       
    Node *L,*R ;
    L=LCA(root->left,n1,n2) ;
    R=LCA(root->right,n1,n2) ;
   
    if(L&&R)
        return root ;
       
    return (L!=NULL)?L:R ;
}

int distance(Node *root,int ele1,int ele2)
{
    if(root==NULL)
        return 0 ;
    int n1,n2 ;
    if(root->data==ele1||root->data==ele2)
        return 1 ;
 
    n1=distance(root->left,ele1,ele2) ;
    if(n1)
        return n1+1 ;
    n2=distance(root->right,ele1,ele2) ;
    if(n2)
        return n2+1 ;
 
}

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