solves diamter of binary tree

Author: anishLearnsToCode

Diff for: README.md

@@ -142,8 +142,8 @@
 | 530 | [Minimum Absolute Difference in BST](https://leetcode.com/problems/minimum-absolute-difference-in-bst) | Easy | [![Java](assets/java.png)](src/MinimumAbsoluteDifferenceInBST.java) [![Python](assets/python.png)](python/minimum_absolute_difference_in_bst.py) |
 | 532 | [K - Diff Pairs in Array](https://leetcode.com/problems/k-diff-pairs-in-an-array) | Easy | [![Java](assets/java.png)](src/KDiffPairsInAnArray.java) [![Python](assets/python.png)](python/k_dif_pairs_in_an_array.py) |
 | 538 | [Convert BST to Greater Tree](https://leetcode.com/problems/convert-bst-to-greater-tree) | Easy | [![Java](assets/java.png)](src/ConvertBSTToGreaterTree.java) [![Python](assets/python.png)](python/convert_bst_to_greater_tree.py) |
-| 541 | [Reverse String II](https://leetcode.com/problems/reverse-string-ii) | Easy | [![Java](assets/java.png)](srcReverseStringII.java/) [![Python](assets/python.png)](python/reverse_string_ii.py) |
-| 543 | [Diameter of Binary Tree](https://leetcode.com/problems/diameter-of-binary-tree) | Easy | |
+| 541 | [Reverse String II](https://leetcode.com/problems/reverse-string-ii) | Easy | [![Java](assets/java.png)](src/ReverseStringII.java/) [![Python](assets/python.png)](python/reverse_string_ii.py) |
+| 543 | [Diameter of Binary Tree](https://leetcode.com/problems/diameter-of-binary-tree) | Easy | [![Java](assets/java.png)](src/DiameterOfBinaryTree.java) [![Python](assets/python.png)](python/diameter_of_binary_tree.py) |
 | 551 | [Student Attendance Record I](https://leetcode.com/problems/student-attendance-record-i) | Easy | |
 | 557 | [Reverse Words in a String III](https://leetcode.com/problems/reverse-words-in-a-string-iii) | Easy | |
 | 559 | [Maximum Depth of N-Ary Tree](https://leetcode.com/problems/maximum-depth-of-n-ary-tree) | Easy | |

Diff for: python/diameter_of_binary_tree.py

@@ -0,0 +1,22 @@
+# Definition for a binary tree node.
+class TreeNode:
+    def __init__(self, val=0, left=None, right=None):
+        self.val = val
+        self.left = left
+        self.right = right
+
+
+class Solution:
+    def __init__(self):
+        self.diameter = 0
+
+    def computerDiameterOfBinaryTree(self, root: TreeNode) -> int:
+        if root is None: return 0
+        leftHeight = self.computerDiameterOfBinaryTree(root.left)
+        rightHeight = self.computerDiameterOfBinaryTree(root.right)
+        self.diameter = max(self.diameter, leftHeight + rightHeight)
+        return 1 + max(leftHeight, rightHeight)
+
+    def diameterOfBinaryTree(self, root: TreeNode) -> int:
+        self.computerDiameterOfBinaryTree(root)
+        return self.diameter

Diff for: src/DiameterOfBinaryTree.java

@@ -0,0 +1,16 @@
+public class DiameterOfBinaryTree {
+    int diameter = 0;
+
+    public int diameterOfBinaryTree(TreeNode root) {
+        computerDiameterOfBinaryTree(root);
+        return diameter;
+    }
+
+    private int computerDiameterOfBinaryTree(TreeNode root) {
+        if (root == null) return 0;
+        int leftHeight = computerDiameterOfBinaryTree(root.left);
+        int rightHeight = computerDiameterOfBinaryTree(root.right);
+        diameter = Math.max(diameter, leftHeight + rightHeight);
+        return 1 + Math.max(leftHeight, rightHeight);
+    }
+}