100.same-tree.ts

class TreeNode {
  val: number;
  left: TreeNode | null;
  right: TreeNode | null;
  constructor(val?: number, left?: TreeNode | null, right?: TreeNode | null) {
    this.val = val === undefined ? 0 : val;
    this.left = left === undefined ? null : left;
    this.right = right === undefined ? null : right;
  }
}

function isSameTree(p: TreeNode | null, q: TreeNode | null): boolean {
  if (p === null && q === null) {
    return true;
  }

  if (p === null || q === null) {
    return false;
  }

  return (
    p.val === q.val &&
    isSameTree(p.left, q.left) &&
    isSameTree(p.right, q.right)
  );
}

const tree1 = new TreeNode(
  3,
  new TreeNode(9),
  new TreeNode(20, new TreeNode(15), new TreeNode(7))
);
const tree2 = new TreeNode(
  3,
  new TreeNode(9),
  new TreeNode(20, new TreeNode(15), new TreeNode(7))
);

console.log(isSameTree(tree1, tree2));