.js

//////////////////
// INSTRUCTIONS //
//////////////////

// Given the root of a binary tree, check whether it is a mirror of itself (i.e., symmetric around its center).

// Input: root = [1,2,2,3,4,4,3]
// Output: true

// Input: root = [1,2,2,null,3,null,3]
// Output: false

const useCase1 = [1, 2, 2, 3, 4, 4, 3];
const output1 = true;

const useCase2 = [1, 2, 2, null, 3, null, 3];
const output2 = false;

const { toUnorderedTree } = require("./helper.js");

const isTreeSymmetric = (tree) => {
  if (!tree) {
    return Error('Not a valid Binary Tree')
  }

  const leftBranch = JSON.stringify(tree.left);

  (function recursiveSymmetryFlip(node) {
    if (node){
      const cLeft = node.left ? JSON.parse(JSON.stringify(node.left)) : null
      const cRight = node.right ? JSON.parse(JSON.stringify(node.right)) : null
      
      if (node.left) {
        node.left.value = cLeft.value ^ cRight.value;
        recursiveSymmetryFlip(node.left);
      }

      if (node.right) {
        node.right.value = cRight.value ^ cLeft.value;
        recursiveSymmetryFlip(node.right);
      }
    }
  })(tree.right);

  const rightBranch = JSON.stringify(tree.right); // we had to flip this and then stringify

  console.log(JSON.stringify(leftBranch))
  console.log(JSON.stringify(rightBranch))

  return leftBranch === rightBranch;
};

module.exports = function () {
  describe("Is Tree Symmetric", () => {
    it("Use Case 1", () => {
      expect(isTreeSymmetric(toUnorderedTree(useCase1))).toEqual(output1);
    });
    // it("Use Case 2", () => {
    //   expect(isTreeSymmetric(toUnorderedTree(useCase2))).toEqual(output2);
    // });
  });
};

// RESULT
// "{\"value\":2,\"left\":{\"value\":3},\"right\":{\"value\":4}}"
// "{\"value\":2,\"left\":{\"value\":7},\"right\":{\"value\":7}}"
//   Is Tree Symmetric
//     ✗ Use Case 1
//       - Expected false to equal true.