Added codes for 7 May

GeeksForGeeks/May/07-5-24/GFG.java

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+//{ Driver Code Starts
+//Initial Template for Java
+
+import java.util.LinkedList; 
+import java.util.Queue; 
+import java.io.*;
+import java.util.*;
+
+class Node{
+    int data;
+    Node left;
+    Node right;
+    Node(int data){
+        this.data = data;
+        left=null;
+        right=null;
+    }
+}
+
+class GFG {
+
+    static Node buildTree(String str){
+
+        if(str.length()==0 || str.charAt(0)=='N'){
+            return null;
+        }
+
+        String ip[] = str.split(" ");
+        // Create the root of the tree
+        Node root = new Node(Integer.parseInt(ip[0]));
+        // Push the root to the queue
+
+        Queue<Node> queue = new LinkedList<>(); 
+
+        queue.add(root);
+        // Starting from the second element
+
+        int i = 1;
+        while(queue.size()>0 && i < ip.length) {
+
+            // Get and remove the front of the queue
+            Node currNode = queue.peek();
+            queue.remove();
+
+            // Get the current node's value from the string
+            String currVal = ip[i];
+
+            // If the left child is not null
+            if(!currVal.equals("N")) {
+
+                // Create the left child for the current node
+                currNode.left = new Node(Integer.parseInt(currVal));
+                // Push it to the queue
+                queue.add(currNode.left);
+            }
+
+            // For the right child
+            i++;
+            if(i >= ip.length)
+                break;
+
+            currVal = ip[i];
+
+            // If the right child is not null
+            if(!currVal.equals("N")) {
+
+                // Create the right child for the current node
+                currNode.right = new Node(Integer.parseInt(currVal));
+
+                // Push it to the queue
+                queue.add(currNode.right);
+            }
+            i++;
+        }
+
+        return root;
+    }
+    static void printInorder(Node root)
+    {
+        if(root == null)
+            return;
+
+        printInorder(root.left);
+        System.out.print(root.data+" ");
+
+        printInorder(root.right);
+    }
+
+    public static void main (String[] args) throws IOException{
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        int t=Integer.parseInt(br.readLine());
+        while(t > 0){
+            String s = br.readLine();
+            Node root = buildTree(s);
+            Tree g = new Tree();
+            ArrayList<Integer> ans = g.reverseLevelOrder(root);
+
+            for (Integer val: ans) 
+                System.out.print(val+" "); 
+            System.out.println();
+            t--;
+        }
+    }
+}
+
+
+
+
+// } Driver Code Ends
+
+
+
+/* 
+class Node
+{
+    int data;
+    Node left, right;
+
+    Node(int item)
+    {
+        data = item;
+        left = right = null;
+    }
+}
+*/
+
+class Tree
+{
+    public ArrayList<Integer> reverseLevelOrder(Node node) 
+    {
+        // code here
+        ArrayList<Integer> result = new ArrayList<>();
+        if (node == null)
+            return result;
+
+        Queue<Node> queue = new LinkedList<>();
+        queue.offer(node);
+
+        while (!queue.isEmpty()) 
+        {
+            int levelSize = queue.size();
+            ArrayList<Integer> levelNodes = new ArrayList<>();
+
+            for (int i = 0; i < levelSize; i++) 
+            {
+                Node current = queue.poll();
+                levelNodes.add(current.data);
+
+                if (current.left != null)
+                    queue.offer(current.left);
+                if (current.right != null)
+                    queue.offer(current.right);
+            }
+
+            result.addAll(0, levelNodes);
+        }
+
+        return result;
+    }
+}      

GeeksForGeeks/May/07-5-24/README.md

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+Time complexity - O(n)
+Space complexity - O(n)

LeetCode/May/07-5-24/README.md

@@ -0,0 +1,2 @@
+Time complexity - O(n)
+Space complexity - O(1)

LeetCode/May/07-5-24/Solution.java

@@ -0,0 +1,28 @@
+/**
+ * Definition for singly-linked list.
+ * public class ListNode {
+ *     int val;
+ *     ListNode next;
+ *     ListNode() {}
+ *     ListNode(int val) { this.val = val; }
+ *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
+ * }
+ */
+class Solution 
+{
+    public ListNode doubleIt(ListNode head) 
+    {
+        if (head.val >= 5)
+            head = new ListNode(0, head);
+
+        for (ListNode curr = head; curr != null; curr = curr.next) 
+        {
+            curr.val *= 2;
+            curr.val %= 10;
+            if (curr.next != null && curr.next.val >= 5)
+                ++curr.val;
+        }
+
+        return head;
+    }
+}