<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:
 long root_result=0;
 

    int dfs(unordered_map<int,vector<int>>& adjlist,int i,vector<int>&count,int prev_node,int curr_depth){
       int total_count=1;
       root_result+=curr_depth;
       for(auto& it:adjlist[i]){
        if(it==prev_node){
            continue;
        }
        total_count+=dfs(adjlist,it,count,i,curr_depth+1);
       }
       count[i]=total_count;
       return total_count;
    }

    void sdfs(unordered_map<int,vector<int>>& adjlist,int parent_node,int prev_node,vector<int>& result,vector<int>& count,int n){
        for(auto& it:adjlist[parent_node]){
            if(it==prev_node){
                continue;
            }
            result[it]=result[parent_node]-count[it]+(n-count[it]);
            sdfs(adjlist,it,parent_node,result,count,n);
        }

    }


    vector<int> sumOfDistancesInTree(int n, vector<vector<int>>& edges) {
        unordered_map<int,vector<int>>adjlist;
        for(int i=0;i<edges.size();i++){
            int u=edges[i][0];
            int v=edges[i][1];
            adjlist[u].push_back(v);
            adjlist[v].push_back(u);
        }
        vector<int>count(n,0);
        vector<int>result(n,0);
       
       dfs(adjlist,0,count,-1,0);
       result[0]=root_result;
       sdfs(adjlist,0,-1,result,count,n);
       return result;
    }

        
};
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