🧠 Solving LeetCode Until I Become Top 1% — Day `54`

The problem is to find the minimum score after removing two edges from a tree with n nodes, where each node has a value. The goal is to minimize the difference between the maximum and minimum XOR values of the three separate trees formed after cutting the edges. A brute force approach would be to try all possible pairs of edges, but this would have a time complexity of O(n³). A more optimized strategy is to build the tree using an adjacency list and perform a depth-first search (DFS) from the root to compute the subtree XOR for every node and track which nodes belong to the subtree of each node. Then, iterate over every pair of nodes, compute the three XOR parts, and evaluate the score. The minimum score found is returned. The code implementation in Python uses a defaultdict to build the graph and a DFS function to compute the subtree XOR and descendants. The time and space complexity of the solution are O(n²). The key takeaways from the problem are the use of XOR and tree DP, and the importance of understanding the problem requirements. The author reflects on their experience solving the problem, acknowledging that they needed help and didn't fully understand the solution at first.