2277. Closest Node to Path in Tree

Explanation:

Given a binary tree and a list of nodes representing a path, we need to find the node in the tree that is closest to the path. The distance between two nodes is defined as the number of edges on the path between them.

To solve this problem, we can traverse the tree and for each node, calculate the distance to each node in the path. We can keep track of the minimum distance encountered so far and the node corresponding to that minimum distance.

Algorithm:

Initialize a variable minDistance to infinity and closestNode to null.
Perform a depth-first search traversal of the tree.
For each node encountered during the traversal, calculate the distance to each node in the path.
Update minDistance and closestNode if a closer node is found.
Return the closestNode at the end of the traversal.

Time Complexity:

The time complexity of this approach is O(N*M), where N is the number of nodes in the tree and M is the number of nodes in the path.

Space Complexity:

The space complexity of this approach is O(H), where H is the height of the tree.

:

View Leetcode Problem

class TreeNode {
    int val;
    TreeNode left;
    TreeNode right;
    TreeNode(int x) { val = x; }
}

class Solution {
    private TreeNode closestNode;
    private int minDistance = Integer.MAX_VALUE;
    
    public TreeNode closestNodeToPath(TreeNode root, List<TreeNode> path) {
        dfs(root, path, 0);
        return closestNode;
    }
    
    private void dfs(TreeNode node, List<TreeNode> path, int depth) {
        if (node == null) return;
        
        for (TreeNode target : path) {
            int distance = getDistance(node, target);
            if (distance < minDistance) {
                minDistance = distance;
                closestNode = node;
            }
        }
        
        dfs(node.left, path, depth + 1);
        dfs(node.right, path, depth + 1);
    }
    
    private int getDistance(TreeNode node1, TreeNode node2) {
        // Calculate distance between two nodes
    }
}

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