public List<List<Integer>> pathSum(Node root, int sum) {
        List<List<Integer>> result = new ArrayList<>();
        List<Integer> current = new ArrayList<>();
        pathSumUtil(root, sum, result, current);
        return result;
    }
Date 10/06/2016
@author Tushar Roy

Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum.

Time complexity O(n)

https://leetcode.com/problems/path-sum/
https://leetcode.com/problems/path-sum-ii/
src/com/interview/tree/PathSum.java