Sum Of path equal to K in binary tree

SumOfPathEqualK.java

public ArrayList<ArrayList<Integer>> pathSum(TreeNode A, int B) {
        
        if(A == null) return null;
        ArrayList<ArrayList<Integer>> res = new ArrayList<ArrayList<Integer>>();
        Deque<TreeNode> deque = new ArrayDeque();
        doItNow(A,B,deque,res);
        return res;
    }
    
    private void doItNow(TreeNode n, int m, Deque<TreeNode> deque,ArrayList<ArrayList<Integer>> res){
        
        if(n == null) return;
        deque.addLast(n);
        
        if(isLeaf(n)){
            checkSumForPath(deque,m,res);
        }
        
        doItNow(n.left,m,deque,res);
        doItNow(n.right,m,deque,res);
        
        deque.removeLast();
        
    }
    private void checkSumForPath(Deque<TreeNode> queue, int sum, ArrayList<ArrayList<Integer>> res){
        if(queue == null) return;
        int tempVar = sum;
        ArrayList<Integer> tempList = new ArrayList<>();
        Deque<TreeNode> tempQueue = new ArrayDeque<>();
        while(!queue.isEmpty()){
            TreeNode temp = queue.remove();
            tempVar -= temp.val;
            tempQueue.add(temp);
        }
        
        while(!tempQueue.isEmpty()){
            TreeNode temp = tempQueue.remove();
            queue.add(temp);
            if(tempVar == 0){
                tempList.add(temp.val);
            }
        }
        
        if(!tempList.isEmpty()){
            res.add(tempList);
        }
    }
    
    private boolean isLeaf(TreeNode node){
        return node.left == null && node.right == null;
    }