Path Sum II — medium DSA Problem

Given the root of a binary tree and an integer targetSum, return all root-to-leaf paths where the sum of the node values equals targetSum. Each path should be returned as a list of node values.

Example 1:

Input:
5 4 8 11 null 13 4 7 2 null null 5 1
22
Output:
5 4 11 2
5 8 4 5

Example 2:

Input:
1 2 3
5
Output:
(empty)

Constraints:

The number of nodes is in the range [0, 5000]
-1000 ≤ Node.val ≤ 1000
-1000 ≤ targetSum ≤ 1000

Input format: First line: BFS level-order (null for missing). Second line: targetSum.

Output format: Each path on its own line, space-separated. Nothing if no paths.