/**
 * Definition for a binary tree node.
 * function TreeNode(val) {
 *     this.val = val;
 *     this.left = this.right = null;
 * }
 */

/**
 * @param {TreeNode} root
 * @param {TreeNode} p
 * @param {TreeNode} q
 * @return {TreeNode}
 */
var lowestCommonAncestor = function (root, p, q) {
  let pPath = [];
  let qPath = [];
  let path = [];
  function travel(node) {
    if (node) {
      path.push(node);
      if (node === p) {
        pPath = path.slice(0);
      }
      if (node === q) {
        qPath = path.slice(0);
      }
      travel(node.left);
      travel(node.right);
      path.pop();
    }
  }
  travel(root);

  let i = 0;
  for (; i < pPath.length || i < qPath.length; i++) {
    if (pPath[i] !== qPath[i]) {
      break;
    }
  }
  return pPath[i - 1];
};

/**
 * @param {number[][]} matrix
 * @return {number[][]}
 */
var transpose = function (matrix) {
  if (!matrix.length) return;
  const numOfCols = matrix[0].length;
  const numOfRows = matrix.length;
  const result = [];
  for (let i = 0; i < numOfCols; i++) {
    result.push([]);
  }
  for (let i = 0; i < numOfCols; i++) {
    for (let j = 0; j < numOfRows; j++) {
      result[i][j] = matrix[j][i];
    }
  }
  return result;
};