#101 LeetCode Symmetric Tree Recursive Solution

symmetricTreeRecursive.js

var isSymmetric = function (root) {
  if (!root) return "no tree was provided 🤔"; // return true
  return dfs(root.left, root.right);

  function dfs(leftNode, rightNode) {
    console.log("running this code block"); // this will run at most for the total number of nodes in the tree
    if (!leftNode && !rightNode) {
      return "you have a perfectly symmetric tree! 🌲"; //return true
    }
    if (
      (leftNode && !rightNode) ||
      (!leftNode && rightNode) ||
      leftNode.value !== rightNode.value
    ) {
      return "your tree is not symmetric 🌴"; // return false
    }
    return (
      dfs(leftNode.right, rightNode.left) && dfs(leftNode.left, rightNode.right)
    );
  }
};