Given a binary tree and a sum, find all root-to-leaf paths where each path‘s sum equals the given sum.
For example:
Given the below binary tree and
Given the below binary tree and
sum = 22,
5
/ 4 8
/ / 11 13 4
/ \ / 7 2 5 1
return
[ [5,4,11,2], [5,8,4,5] ]
1 class Solution { 2 List<List<Integer>> res = new ArrayList<>(); 3 public List<List<Integer>> pathSum(TreeNode root, int sum) { 4 List<Integer> curres = new ArrayList<Integer>(); 5 help(root,0,sum,curres); 6 return res; 7 } 8 private void help(TreeNode root,int sum ,int target,List<Integer> curres){ 9 if(root == null) return ; 10 curres.add(root.val); 11 if(root.left==null && root.right==null && sum+root.val==target) 12 res.add(new ArrayList(curres)); 13 help(root.left,sum+root.val,target,curres); 14 help(root.right,sum+root.val,target,curres); 15 curres.remove(curres.size()-1); 16 } 17 }
