Find neatest (lowest) common ancestor of two given nodes X1 and X2

/* Find neatest (lowest) common   ancestor of two given nodes X1 and X2

input format :  an  integer T denoting number of test cases followed by 3 T Lines as each test case will
contain 3 lines 
first line N
second line elements
where the no at index i is the parent of node i . The parent of root  is -1
third line X1 and X2

output:
for each test case out put a single line that has the  neatest (lowest) common   ancestor of two given nodes X1 and X2


*/
#include<stdio.h>
#include <queue>
#include <vector>

using namespace std;
# define MAX_Q_SIZE  25
// A tree node
struct Node
{
 int key;
 struct Node *left, *right;
};

// Utility function to create new Node
Node *newNode(int key)
{
 Node *temp = new Node;
 temp->key = key;
 temp->left = temp->right = NULL;
 return (temp);
}

// Creates a node with key as 'i'. If i is root, then it changes
// root. If parent of i is not created, then it creates parent first
void createNode(int parent[], int i, Node *created[], Node **root)
{
 // If this node is already created
 if (created[i] != NULL)
  return;

 // Create a new node and set created[i]
 created[i] = newNode(i);

 // If 'i' is root, change root pointer and return
 if (parent[i] == -1)
 {
  *root = created[i];
  return;
 }

 // If parent is not created, then create parent first
 if (created[parent[i]] == NULL)
  createNode(parent, parent[i], created, root);

 // Find parent pointer
 Node *p = created[parent[i]];

 // If this is first child of parent
 if (p->left == NULL)
  p->left = created[i];
 else // If second child
  p->right = created[i];
}

// Creates tree from parent[0..n-1] and returns root of the created tree
Node *createTree(int parent[], int n)
{
 // Create an array created[] to keep track
 // of created nodes, initialize all entries
 // as NULL
 Node *created[n];
 for (int i=0; i<n; i++)
  created[i] = NULL;

 Node *root = NULL;
 for (int i=0; i<n; i++)
  createNode(parent, i, created, &root);

 return root;
}

// Finds the path from root node to given root of the tree, Stores the
// path in a vector path[], returns true if path exists otherwise false
bool findPath(Node *root, vector<int> &path, int k)
{
    // base case
    if (root == NULL) return false;
 
    // Store this node in path vector. The node will be removed if
    // not in path from root to k
    path.push_back(root->key);
 
    // See if the k is same as root's key
    if (root->key == k)
        return true;
 
    // Check if k is found in left or right sub-tree
    if ( (root->left && findPath(root->left, path, k)) ||
         (root->right && findPath(root->right, path, k)) )
        return true;
 
    // If not present in subtree rooted with root, remove root from
    // path[] and return false
    path.pop_back();
    return false;
}

// Returns LCA if node n1, n2 are present in the given binary tree,
// otherwise return -1
int findLCA(Node *root, int n1, int n2)
{
    // to store paths to n1 and n2 from the root
    vector<int> path1, path2;
 
    // Find paths from root to n1 and root to n1. If either n1 or n2
    // is not present, return -1
    if ( !findPath(root, path1, n1) || !findPath(root, path2, n2))
          return -1;
 
    /* Compare the paths to get the first different value */
    int i;
    for (i = 0; i < path1.size() && i < path2.size() ; i++)
        if (path1[i] != path2[i])
            break;
    return path1[i-1];
}





// Driver method
int main()
{
    int x1,x2;
    int k,T,n;
 int result[100]   ;
 int parent[1000];


 scanf("%d",&T);
 k=T;

 while(k>=1)
 {
 scanf("%d",&n);
  for(int i=0;i<n;i++)
     scanf("%d",&parent[i]);
 Node *root = createTree(parent, n);
   
     scanf("%d%d",&x1,&x2);
   result[k]=findLCA(root, x1, x2);
   //printf("\nresult %d",result[k]);
   k--;
 }
 
  for(int j=T;j>=1;j--)
   printf("\n%d",result[j]);
   
 
}


input:
2
6
5 -1 1 1 5 2
0 3
7
-1 0 0 1 1 3 5
6  5

o/p
1
5