根到叶路径上的不足节点

/*
 * In this Java Stream solution, we cannot directly use streams to handle tree traversal due to their recursive nature.
 * However, the logic remains similar, and we'll use traditional recursive methods but explain using Stream API concepts.
 * This solution involves traversing the tree using a recursive function that calculates the maximum path sum from the root to any leaf.
 */
public class TreeNode {
    int val;
    TreeNode left;
    TreeNode right;
    TreeNode(int x) { val = x; }
}

public class Solution {
    public TreeNode sufficientSubset(TreeNode root, int limit) {
        return dfs(root, 0, limit);
    }
    private TreeNode dfs(TreeNode node, int sum, int limit) {
        if (node == null) return null;
        sum += node.val;
        if (node.left == null && node.right == null) {
            return sum < limit ? null : node;
        }
        node.left = dfs(node.left, sum, limit);
        node.right = dfs(node.right, sum, limit);
        return node.left == null && node.right == null ? null : node;
    }
}