### Instruction:
There is an undirected connected tree with `n` nodes labeled from `0` to `n - 1` and `n - 1` edges.

You are given a **0-indexed** integer array `nums` of length `n` where `nums[i]` represents the value of the `ith` node. You are also given a 2D integer array `edges` of length `n - 1` where `edges[i] = [ai, bi]` indicates that there is an edge between nodes `ai` and `bi` in the tree.

Remove two **distinct** edges of the tree to form three connected components. For a pair of removed edges, the following steps are defined:

1.  Get the XOR of all the values of the nodes for **each** of the three components respectively.
2.  The **difference** between the **largest** XOR value and the **smallest** XOR value is the **score** of the pair.

*   For example, say the three components have the node values: `[4,5,7]`, `[1,9]`, and `[3,3,3]`. The three XOR values are `4 ^ 5 ^ 7 = **6**`, `1 ^ 9 = **8**`, and `3 ^ 3 ^ 3 = **3**`. The largest XOR value is `8` and the smallest XOR value is `3`. The score is then `8 - 3 = 5`.

Return _the **minimum** score of any possible pair of edge removals on the given tree_.

**Example 1:**

**Input:** nums = \[1,5,5,4,11\], edges = \[\[0,1\],\[1,2\],\[1,3\],\[3,4\]\]
**Output:** 9
**Explanation:** The diagram above shows a way to make a pair of removals.
- The 1st component has nodes \[1,3,4\] with values \[5,4,11\]. Its XOR value is 5 ^ 4 ^ 11 = 10.
- The 2nd component has node \[0\] with value \[1\]. Its XOR value is 1 = 1.
- The 3rd component has node \[2\] with value \[5\]. Its XOR value is 5 = 5.
The score is the difference between the largest and smallest XOR value which is 10 - 1 = 9.
It can be shown that no other pair of removals will obtain a smaller score than 9.

**Example 2:**

**Input:** nums = \[5,5,2,4,4,2\], edges = \[\[0,1\],\[1,2\],\[5,2\],\[4,3\],\[1,3\]\]
**Output:** 0
**Explanation:** The diagram above shows a way to make a pair of removals.
- The 1st component has nodes \[3,4\] with values \[4,4\]. Its XOR value is 4 ^ 4 = 0.
- The 2nd component has nodes \[1,0\] with values \[5,5\]. Its XOR value is 5 ^ 5 = 0.
- The 3rd component has nodes \[2,5\] with values \[2,2\]. Its XOR value is 2 ^ 2 = 0.
The score is the difference between the largest and smallest XOR value which is 0 - 0 = 0.
We cannot obtain a smaller score than 0.

**Constraints:**

*   `n == nums.length`
*   `3 <= n <= 1000`
*   `1 <= nums[i] <= 108`
*   `edges.length == n - 1`
*   `edges[i].length == 2`
*   `0 <= ai, bi < n`
*   `ai != bi`
*   `edges` represents a valid tree.


### Response:


def dfs(node, parent, xor_values, tree):
    xor_value = xor_values[node]
    for child in tree[node]:
        if child != parent:
            xor_value ^= dfs(child, node, xor_values, tree)
    return xor_value


def minimumScore(nums, edges):
    n = len(nums)
    tree = [[] for _ in range(n)]

    for edge in edges:
        tree[edge[0]].append(edge[1])
        tree[edge[1]].append(edge[0])

    xor_values = [dfs(i, -1, nums, tree) for i in range(n)]

    ans = float('inf')
    for i in range(n):
        for j in range(i + 1, n):
            xor1 = xor_values[i]
            xor2 = xor_values[j] ^ nums[i]
            xor3 = nums[i] ^ nums[j]
            max_xor = max(xor1, xor2, xor3)
            min_xor = min(xor1, xor2, xor3)
            ans = min(ans, max_xor - min_xor)

    return ans
