text: /**
   * Definition for a binary tree node.
   * function TreeNode(val, left, right) {
   *     this.val = (val===undefined ? 0 : val)
   *     this.left = (left===undefined ? null : left)
   *     this.right = (right===undefined ? null : right)
   * }
   */
  /**
   * @param {TreeNode} root
   * @return {number}
   */
  const maxPathSum = function (root) {
    let maxSum = Number.MIN_SAFE_INTEGER
  
    const process = (node) => {
      if (node === null) {
        return 0
      }
  
      const leftSum = Math.max(0, process(node.left))
      const rightSum = Math.max(0, process(node.right))
  
      maxSum = Math.max(maxSum, leftSum + rightSum + node.val)
  
      return Math.max(leftSum, rightSum) + node.val
    }
  
    process(root)
  
    return maxSum
  }
  
  module.exports = maxPathSum
  