Given the root of a binary tree and an integer targetSum, return true if the tree has a root-to-leaf path such that adding up all the values along the path equals targetSum.

A leaf is a node with no children.

Example 1:

pathsum1

  • Input: root = [5,4,8,11,null,13,4,7,2,null,null,null,1], targetSum = 22
  • Output: true
  • Explanation: The root-to-leaf path with the target sum is shown.

Example 2:

pathsum2

  • Input: root = [1,2,3], targetSum = 5
  • Output: false
  • Explanation: There are two root-to-leaf paths in the tree:
  • (1 –> 2): The sum is 3.
  • (1 –> 3): The sum is 4.
  • There is no root-to-leaf path with sum = 5.

Example 3:

  • Input: root = [], targetSum = 0
  • Output: false
  • Explanation: Since the tree is empty, there are no root-to-leaf paths.

Constraints:

  • The number of nodes in the tree is in the range [0, 5000].
  • -1000 <= Node.val <= 1000
  • -1000 <= targetSum <= 1000