Merge pull request #224 from neha030/dev1

Diameter of Binary Tree added

Author: smv1999

Data Structures/Trees/Diameter_Binary_Tree.cpp

@@ -0,0 +1,82 @@
+// The path which has the highest number of nodes is called the diameter of the binary tree.
+#include<bits/stdc++.h>
+using namespace std;
+class node
+{   
+    public:
+    int data;
+    node *left;
+    node *right;
+};
+node* newnode(int data)
+{
+  node *newblock= new node();
+  newblock->left=NULL;
+  newblock->right=NULL;
+}
+// calculating the height of the binary tree.
+int height (node *p)
+{
+    if(p==NULL)
+    return 0;
+    int left=height(p->left);
+    int right=height(p->right);
+    int h;
+    if(left>right)
+    {
+        h=1+left;
+    }
+    else
+    {
+        h=1+right;
+    }
+    return h;
+}
+// calculating the diameter of the binary tree.
+int final_diameter(node *p)
+{
+    if(p==NULL)
+    return 0;
+    //value of the left node is passed to height function to calculate height of left sub tree.
+    int left_height=height(p->left); 
+    //value of the right node is passed to height function to calculate height of right sub tree.
+    int right_height=height(p->right);
+    //calculating diameter of left subtree which does not include root node
+    int left_diameter=final_diameter(p->left);
+    //calculating diameter of right subtree which does not include root node
+    int right_diameter=final_diameter(p->right);
+    int final=max(left_height+right_height+1 , max(left_diameter,right_diameter));
+    return final;
+}
+int main()
+{   
+    // formation of a binary tree
+    node * root=newnode(5);
+    root->left=newnode(3);
+    root->left->left=newnode(9);
+    root->right=newnode(1);
+    root->left->right=newnode(6);
+    root->left->right->left=newnode(7);
+    // printing the final value
+    cout<<"Diameter:"<<final_diameter(root);
+    return 0;
+}
+
+/*
+    OUTPUT
+
+         5
+        / \         
+       3   1      
+      / \
+     9   6
+        /
+       7
+       
+     Diameter:5
+     
+ the longest path is from the node conatining value '7'
+ to node containing value '1'.
+   
+
+*/