<p>There is an undirected connected tree with <code>n</code> nodes labeled from <code>0</code> to <code>n - 1</code> and <code>n - 1</code> edges.</p>

<p>You are given the integer <code>n</code> and the array <code>edges</code> where <code>edges[i] = [a<sub>i</sub>, b<sub>i</sub>]</code> indicates that there is an edge between nodes <code>a<sub>i</sub></code> and <code>b<sub>i</sub></code> in the tree.</p>

<p>Return an array <code>answer</code> of length <code>n</code> where <code>answer[i]</code> is the sum of the distances between the <code>i<sup>th</sup></code> node in the tree and all other nodes.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/07/23/lc-sumdist1.jpg" style="width: 304px; height: 224px;" />
<pre>
<strong>Input:</strong> n = 6, edges = [[0,1],[0,2],[2,3],[2,4],[2,5]]
<strong>Output:</strong> [8,12,6,10,10,10]
<strong>Explanation:</strong> The tree is shown above.
We can see that dist(0,1) + dist(0,2) + dist(0,3) + dist(0,4) + dist(0,5)
equals 1 + 1 + 2 + 2 + 2 = 8.
Hence, answer[0] = 8, and so on.
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/07/23/lc-sumdist2.jpg" style="width: 64px; height: 65px;" />
<pre>
<strong>Input:</strong> n = 1, edges = []
<strong>Output:</strong> [0]
</pre>

<p><strong class="example">Example 3:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/07/23/lc-sumdist3.jpg" style="width: 144px; height: 145px;" />
<pre>
<strong>Input:</strong> n = 2, edges = [[1,0]]
<strong>Output:</strong> [1,1]
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= n &lt;= 3 * 10<sup>4</sup></code></li>
	<li><code>edges.length == n - 1</code></li>
	<li><code>edges[i].length == 2</code></li>
	<li><code>0 &lt;= a<sub>i</sub>, b<sub>i</sub> &lt; n</code></li>
	<li><code>a<sub>i</sub> != b<sub>i</sub></code></li>
	<li>The given input represents a valid tree.</li>
</ul>

class Solution {
public:
   pair<int,int> dfs(int node,vector<int>&par,vector<pair<int,int>>&cal,unordered_map<int,vector<int>>&mp,vector<int>&vis){
      vis[node]=1;
      int no=0;
      int d=0;
      for(auto it:mp[node]){
        if(vis[it]==0){
            vis[it]=1;
            par[it]=node;
          pair<int,int>k=dfs(it,par,cal,mp,vis);
          d=d+k.second+k.first;
          no=no+k.second;
        }
      }
    return cal[node]={d,no+1};
         
   }
   void solve(int node,vector<int>&par,vector<pair<int,int>>&cal,vector<int>&ans,vector<int>&vis,unordered_map<int,vector<int>>&mp){
       queue<int>q;
       q.push(node);
      vis[node]=1;
      int n=par.size();
       while(!q.empty()){
        int des=q.front();q.pop();
            for(auto it:mp[des]){
                if(vis[it]==0){
                    vis[it]=1;
                    q.push(it);
                }
            
            }
         
        if(par[des]!=-1){
          int up=ans[par[des]];
          pair<int,int>dow=cal[des];
          int x=up-dow.first-dow.second;
         int y=n-dow.second;
         ans[des]=dow.first+x+y;
          }

       }



    
   }
    vector<int> sumOfDistancesInTree(int n, vector<vector<int>>& edges) {
        vector<int>par(n,-1);
        vector<pair<int,int>>cal(n);
        vector<int>vis(n,0);
        vector<int>ans(n,0);
        unordered_map<int,vector<int>>mp;
        for(auto it:edges){
            mp[it[0]].push_back(it[1]);
             mp[it[1]].push_back(it[0]);
        }
       pair<int,int>j=dfs(0,par,cal,mp,vis);
       for(int i=0;i<n;i++){
         vis[i]=0;
        //cout<< par[i];
       }
       ans[0]=cal[0].first;
       solve(0,par,cal,ans,vis,mp);
    //    for(int i=0;i<n;i++){
    //      cout<<par[i]<<" ";
    //    }
    //    cout<<endl;
    //    for(int i=0;i<n;i++){
    //      cout<<cal[i]<<" ";
    //    }
    //    cout<<endl;
          return ans;
    }
};
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