Diameter of Binary Tree

543. Diameter of Binary Tree

Solution

1. The same as 1 + left tree’s height + right tree’s height
2. Keep a variable to track the current longest path
3. As we checking each node’s height, the variable will get updated and store the maximum value in the end.
   ```python def diameterOfBinaryTree(self, root): “”” :type root: TreeNode :rtype: int “”” self.ans = 0 self.depth(root) return self.ans

def depth(self, root): if root is None: return 0 left = self.depth(root.left) right = self.depth(root.right) self.ans = max(self.ans, left + right) return 1 + max(left, right) ```