Title: Path Sum II Source: leetcode.com Given a binary tree and a sum, find all root-to-leaf paths where each path’s sum equals the given sum. sum = 22 5 / \ 4 8 / / \ 11 13 4 / \ / \ 7 2 5 1 1234567               5             / \            4   8           /   / \          11  13  4         ...