Count Leaves in Binary Tree

Author: akashmodak97

Geeks For Geeks/Count Leaves in Binary Tree.cpp

@@ -1,177 +1,52 @@
-/* Geeks for Geeks */
-/* Title - Count Leaves in Binary Tree */
-/* Created By - Akash Modak */
-/* Date - 11/10/2020 */
-
-// Given a Binary Tree of size N , You have to count leaves in it. For example, there are two leaves in following tree
-
-//         1
-//      /      \
-//    10      39
-//   /
-// 5
-
-// Input:
-// First line of input contains the number of test cases T. For each test case, there will be only a single line of input which is a string representing the tree as described below: 
-
-// The values in the string are in the order of level order traversal of the tree where, numbers denote node values, and a character “N” denotes NULL child.
-
-// For example:
-
-// For the above tree, the string will be: 1 2 3 N N 4 6 N 5 N N 7 N
-
-// Output:
-// For each test case print the count of leaves.
-// Your Task:
-// You don't have to take input. Complete the function countLeaves() that takes root node of given tree as parameter and returns the count of leaves in tree . The printing is done by the driver code.
-// Constraints:
-// 1<= T <= 30
-// 1<= N <= 104
-// Example:
-// Input:
-// 2
-// 3 4 2 
-// 4 8 10 7 N 5 1 3 
-// Output:
-// 2
-// 3
-// Explanation:
-// Test Case 2:  Given Tree is 
-//                                  4
-//                                /     \
-//                             8       10
-//                           /          /      \
-//                        7          5        1
-//                       /
-//                      3
-// Three leaves are 3 , 5 and 1.
-
-// Note:The Input/Ouput format and Example given below is used for system's internal purpose, and should be used by a user for Expected Output only. As it is a function problem, hence a user should not read any input from stdin/console, and should not print anything on stdout/console. The task is to complete the function specified, and not to write the full code.
-
-// { Driver Code Starts
-#include <bits/stdc++.h>
-using namespace std;
-
-struct Node
-{
-    int data;
-    struct Node *left;
-    struct Node *right;
-};
-Node* newNode(int val)
-{
-    Node* temp = new Node;
-    temp->data = val;
-    temp->left = NULL;
-    temp->right = NULL;
-    
-    return temp;
-}
-Node* buildTree(string str)
-{   
-    // Corner Case
-    if(str.length() == 0 || str[0] == 'N')
-            return NULL;
-    
-    // Creating vector of strings from input 
-    // string after spliting by space
-    vector<string> ip;
-    
-    istringstream iss(str);
-    for(string str; iss >> str; )
-        ip.push_back(str);
-        
-    // Create the root of the tree
-    Node* root = newNode(stoi(ip[0]));
-        
-    // Push the root to the queue
-    queue<Node*> queue;
-    queue.push(root);
-        
-    // Starting from the second element
-    int i = 1;
-    while(!queue.empty() && i < ip.size()) {
-            
-        // Get and remove the front of the queue
-        Node* currNode = queue.front();
-        queue.pop();
-            
-        // Get the current node's value from the string
-        string currVal = ip[i];
-            
-        // If the left child is not null
-        if(currVal != "N") {
-                
-            // Create the left child for the current node
-            currNode->left = newNode(stoi(currVal));
-                
-            // Push it to the queue
-            queue.push(currNode->left);
-        }
-            
-        // For the right child
-        i++;
-        if(i >= ip.size())
-            break;
-        currVal = ip[i];
-            
-        // If the right child is not null
-        if(currVal != "N") {
-                
-            // Create the right child for the current node
-            currNode->right = newNode(stoi(currVal));
-                
-            // Push it to the queue
-            queue.push(currNode->right);
-        }
-        i++;
-    }
-    
-    return root;
-}
-int countLeaves(struct Node* root);
-
-int main()
-{
-    int t;
-	scanf("%d ",&t);
-    while(t--)
-    {
-        string s;
-		getline(cin,s);
-		Node* root = buildTree(s);
-		cout<< countLeaves(root)<<endl;
-    }
-    return 0;
-}
-// } Driver Code Ends
-
-
-//User function Template for C++
-
-/* A binary tree node has data, pointer to left child
-   and a pointer to right child  
-struct Node
-{
-    int data;
-    Node* left;
-    Node* right;
-}; */
-
-/* Should return count of leaves. For example, return
-    value should be 2 for following tree.
-         10
-      /      \ 
-   20       30 */
-int countLeaves(Node* root)
-{
-  // Your code here
-  if(root==NULL)
-  return 0;
-  
-  if(root->left==NULL and root->right==NULL)
-  return 1;
-  int l = countLeaves(root->left);
-  int r = countLeaves(root->right);
-  return l+r;
-}
+/* Geeks for Geeks */
+/* Title - Count Leaves in Binary Tree */
+/* Created By - Akash Modak */
+/* Date - 23/08/2021 */
+
+// Given a Binary Tree of size N , You have to count leaves in it. For example, there are two leaves in following tree
+
+//         1
+//      /      \
+//    10      39
+//   /
+// 5
+
+ 
+
+// Example 1:
+
+
+// Input:
+// Given Tree is 
+//                4
+//              /   \
+//             8     10
+//            /     /   \
+//           7     5     1
+//          /
+//         3 
+// Output:
+// 3
+// Explanation: 
+// Three leaves are 3 , 5 and 1.
+ 
+
+// Your Task:
+// You don't have to take input. Complete the function countLeaves() that takes root node of given tree as parameter and returns the count of leaves in tree . The printing is done by the driver code.
+
+
+int countLeaves(Node* root)
+{
+  // Your code here
+  
+  if(root == NULL){
+      return 0;
+  }
+  
+  if(root->left == NULL and root->right == NULL){
+      return 1;
+  }
+  
+  return countLeaves(root->left) + countLeaves(root->right);
+  
+}