content: package LeetCode.Easy.PathSum;
  
  /*
    112. Path Sum
  
    Share
    Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum.
  
    Note: A leaf is a node with no children.
  
    Example:
  
    Given the below binary tree and sum = 22,
  
         5
        / \
       4   8
      /   / \
     11  13  4
    /  \      \
   7    2      1
    return true, as there exist a root-to-leaf path 5->4->11->2 which sum is 22.
  */
  
  class TreeNode {
    int val;
    TreeNode left;
    TreeNode right;
  
    TreeNode() {}
  
    TreeNode(int val) {
      this.val = val;
    }
  
    TreeNode(int val, TreeNode left, TreeNode right) {
      this.val = val;
      this.left = left;
      this.right = right;
    }
  }
  
  public class Solution {
    public boolean hasPathSum(TreeNode root, int sum) {
      if (root == null) return false;
  
      if (root.val == sum && root.left == null && root.right == null) return true;
  
      return hasPathSum(root.left, sum - root.val) || hasPathSum(root.right, sum - root.val);
    }
  
    public static void main(String[] args) {
      Solution solution = new Solution();
  
      TreeNode root = new TreeNode(5);
  
      root.left = new TreeNode(4);
      root.left.left = new TreeNode(11);
      root.left.left.left = new TreeNode(7);
      root.left.left.right = new TreeNode(2);
  
      root.right = new TreeNode(8);
      root.right.left = new TreeNode(13);
      root.right.right = new TreeNode(4);
      root.right.right.left = new TreeNode(1);
  
      // should be true
      System.out.println(solution.hasPathSum(root, 22));
    }
  }
  