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Java-based LeetCode algorithm problem solutions, regularly updated
834\. Sum of Distances in Tree
Hard
There is an undirected connected tree with `n` nodes labeled from `0` to `n - 1` and `n - 1` edges.
You are given the integer `n` and the array `edges` where edges[i] = [ai, bi]
indicates that there is an edge between nodes ai
and bi
in the tree.
Return an array `answer` of length `n` where `answer[i]` is the sum of the distances between the ith
node in the tree and all other nodes.
**Example 1:**
![](https://assets.leetcode.com/uploads/2021/07/23/lc-sumdist1.jpg)
**Input:** n = 6, edges = [[0,1],[0,2],[2,3],[2,4],[2,5]]
**Output:** [8,12,6,10,10,10]
**Explanation:** 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.
**Example 2:**
![](https://assets.leetcode.com/uploads/2021/07/23/lc-sumdist2.jpg)
**Input:** n = 1, edges = []
**Output:** [0]
**Example 3:**
![](https://assets.leetcode.com/uploads/2021/07/23/lc-sumdist3.jpg)
**Input:** n = 2, edges = [[1,0]]
**Output:** [1,1]
**Constraints:**
* 1 <= n <= 3 * 104
* `edges.length == n - 1`
* `edges[i].length == 2`
* 0 <= ai, bi < n
* ai != bi
* The given input represents a valid tree.