1026

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
void inorder(TreeNode* root,vector<int>&v){
    if(root==NULL)
    return ;
    inorder(root->left,v);
    v.push_back(root->val);
    inorder(root->right,v); 
}

void  subgraph(TreeNode* root,vector<pair<int,vector<int>>>&mp){
    // vector<int>v;
    if(root==NULL)
    return ;
subgraph(root->left,mp);
vector<int>v;

    inorder(root,v);
    if(v.size()>0)
    mp.push_back({root->val,v});

    subgraph(root->right,mp);

}
    int maxAncestorDiff(TreeNode* root) {
       
// map<int,vector<int>>&mp;
vector<pair<int,vector<int>>>mp;
vector<int>ans;
subgraph(root,mp);

// for(auto i:mp){
//     int a=i.first;
//     cout<<"a is"<<a<<endl;
//     vector<int>v=i.second;
//  for(auto j:v)
//  cout<<j<<" ";
//  cout<<endl;


// }
for(auto i:mp){
    int a=i.first;
    vector<int>v=i.second;

    if(v.size()>1){
            sort(v.begin(),v.end());

        int a1=abs(a-v[v.size()-1]);
        int b1=abs(a-v[0]);
        int mx=max({a1,b1});
        ans.push_back(mx);
    }
}

return *max_element(ans.begin(),ans.end());
        
    }
};