Minimum Depth of Binary Tree LeetCode

Recursion:
public int minDepth(TreeNode root) {
        if (root == null) return 0;
        if (root.left == null && root.right == null) {
            return 1;
        }
        else if (root.left != null && root.right != null) {
            return 1+Math.min(minDepth(root.left), minDepth(root.right));
        }
        else if (root.left == null && root.right != null) {
            return 1+minDepth(root.right);
        } else {
        return 1+minDepth(root.left);
        }
    }

Non-Recursion:
Why we use this method. Sometimes the tree is not balanced. This way will save lots of time. The worst of time complexity is O(n).
public int minDepth(TreeNode root) {
        if (root == null) return 0;
     
        Queue<TreeNode> nodeQueue = new LinkedList<TreeNode>();
        Queue<Integer> intQueue = new LinkedList<Integer>();
        nodeQueue.add(root);
        intQueue.add(1);
     
        while (!nodeQueue.isEmpty()) {
            TreeNode currNode = nodeQueue.poll();
            int currDepth = intQueue.poll();
         
            if (currNode.left != null) {
                nodeQueue.add(currNode.left);
                intQueue.add(currDepth+1);
            }
            if (currNode.right != null) {
                nodeQueue.add(currNode.right);
                intQueue.add(currDepth+1);
            }
            if (currNode.right == null && currNode.left == null) {
                return currDepth;
            }
        }
        return -1;//Should never reach here.
    }