543. Diameter of Binary Tree

Author: manahiliqbal

diameterOfBinaryTree.cpp

@@ -0,0 +1,26 @@
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
+ *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
+ *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
+ * };
+ */
+class Solution {
+public:
+    int diameterOfBinaryTree(TreeNode* root) {
+        int diameter = 0;
+        Helper(root, diameter);
+        return diameter;
+    }
+    int Helper (TreeNode* root, int& diameter){
+        if (root == NULL) return 0;
+        int leftPath = Helper(root->left, diameter);
+        int rightPath = Helper(root->right, diameter);
+        diameter = max(diameter, leftPath + rightPath);
+        return max(leftPath, rightPath) + 1;
+    }
+};