[剑指offer] 二叉树中和为某一值的路径

import java.util.ArrayList;
/**
public class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;
    }
}
*/
public class Solution {
    ArrayList<ArrayList<Integer> > res = new ArrayList<ArrayList<Integer> >();
    ArrayList<Integer> temp = new ArrayList<Integer>();
    public ArrayList<ArrayList<Integer>> FindPath(TreeNode root,int target) {
        if(root == null)
            return res;
        target -= root.val;
        temp.add(root.val);
        if(target == 0 && root.left == null && root.right == null)
            res.add(new ArrayList<Integer>(temp));
        else{
            FindPath(root.left, target);
            FindPath(root.right, target);
        }
        temp.remove(temp.size()-1);
        return res;
    }        
}