4.9---二叉树路径和（CC150）

//注意，1，要判断null；2，要注意ArrayList直接复制会被一起改变。要通过new的方式来操作。
public class Solution {
    public static void main(String[] args){
        TreeNode root = new TreeNode(10);
        root.left = new TreeNode(5);
        root.right = new TreeNode(12);
        root.left.left = new TreeNode(4);
        root.left.right = new TreeNode(7);
        ArrayList<ArrayList<Integer>> test = FindPath(null,22);
        for(ArrayList<Integer> tmp : test){
            System.out.println(tmp);
        }
    }
    public static ArrayList<ArrayList<Integer>> FindPath(TreeNode root,int target) {
        ArrayList<ArrayList<TreeNode>> res = new ArrayList();

        ArrayList<ArrayList<Integer>> ans = new ArrayList();
        if(root == null || root.val > target  ) return ans;
        ArrayList<TreeNode> tmp = new ArrayList();
        tmp.add(root);
        res.add(tmp);
        int flag = 1;
        while(flag != 0){
            System.out.println(123);
            flag = 0;
            ArrayList<ArrayList<TreeNode>> res2 = new ArrayList();
            for(ArrayList<TreeNode> a : res){
                ArrayList<TreeNode> left = new ArrayList(a);
                ArrayList<TreeNode> right = new ArrayList(a);
                
                TreeNode tmp1 = a.get(a.size()-1).left;
                TreeNode tmp2 = a.get(a.size()-1).right;
                if(tmp1 != null ){
                    System.out.println("tmp1=" + tmp1.val);
                    left.add(tmp1);
                    res2.add(left);
                    
                    flag = 1;
                }
            
                if(tmp2 != null ){
                    right.add(tmp2);
                    res2.add(right);
                    flag = 1;
                }
                if(tmp1 == null && tmp2 == null){
                    res2.add(left);
                }
                
            }
            res = new ArrayList(res2);
            for(ArrayList<TreeNode> a : res){
                for(TreeNode t : a){
                    System.out.print(t.val+" ");
                }
                System.out.println("");
            }
            System.out.println(flag);
            System.out.println("res.size()="+ res.size());
        }
        
        for(ArrayList<TreeNode> a : res){
            if(sum(a) == target){
                ArrayList<Integer> al = new ArrayList();
                for(TreeNode t : a){
                    al.add(t.val);
                }
                
                ans.add(al);
            }
        }
        
        
        return ans;
    }
    
    public static int sum (ArrayList<TreeNode> tmp){
        int sum = 0;
        for(TreeNode t : tmp){
            sum += t.val;
        }
        return sum;
    }
}