https://leetcode.com/problems/path-sum-ii/
找出所有根节点到叶子节点的路径
public class Solution { public List<List<Integer>> pathSum(TreeNode root, int sum) { List<List<Integer>> res = new LinkedList(); pathSum(root, sum, res, new LinkedList()); return res; } private void pathSum(TreeNode root, int sum, List<List<Integer>> res, List<Integer> list) { if (root == null) { return; } list.add(root.val); if (root.left == null && root.right == null && root.val == sum) { res.add(new LinkedList(list)); // 特殊情况也不要忘了删除！ list.remove(list.size() - 1); return; } pathSum(root.left, sum - root.val, res, list); pathSum(root.right, sum - root.val, res, list); list.remove(list.size() - 1); } }
