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
sum
= 22
,
5 / \ 4 8 / / \ 11 13 4 / \ / \ 7 2 5 1
return
[ [5,4,11,2], [5,8,4,5] ]
/**
* Definition for binary tree
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
import java.util.*;
public class Solution {
private ArrayList<ArrayList<Integer>> lists = new ArrayList<ArrayList<Integer>>();
private Stack<Integer> s = new Stack<Integer>();
public ArrayList<ArrayList<Integer>> pathSum(TreeNode root, int sum) {
if(root == null){
return lists;
}
pathSumCore(root,sum);
return lists;
}
private void pathSumCore(TreeNode root,int sum){
if(root ==null) return;
s.push(root.val);
if(sum == root.val && root.left==null &&root.right ==null){
ArrayList<Integer> list = new ArrayList<Integer>();
for(Integer i:s){
list.add(i);
}
lists.add(list);
}
pathSum(root.left,sum-root.val);
pathSum(root.right,sum-root.val);
s.pop();
}
}