Added codes for 18 March

GeeksForGeeks/March/18-3-24/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);
+        	    Solution g = new Solution();
+                ArrayList <Integer> res = g.levelOrder(root);
+                for (Integer num : res) System.out.print(num + " ");
+    			System.out.println();
+                t--;
+
+        }
+    }
+
+}
+
+
+// } Driver Code Ends
+
+
+//User function Template for Java
+
+/*
+class Node
+{
+    int data;
+    Node left, right;
+
+    Node(int item)
+    {
+        data = item;
+        left = right = null;
+    }
+}
+*/
+class Solution
+{
+    //Function to return the level order traversal of a tree.
+    static ArrayList <Integer> levelOrder(Node root) 
+    {
+        // Your code here
+        Queue<Node> queue = new LinkedList<Node>();
+        ArrayList<Integer> ans = new ArrayList<>();
+        queue.add(root);
+        while (!queue.isEmpty()) 
+        {
+            Node tempNode = queue.poll();
+            ans.add(tempNode.data);
+
+            if (tempNode.left != null)
+                queue.add(tempNode.left);
+
+            if (tempNode.right != null)
+                queue.add(tempNode.right);
+        }
+
+        return ans;
+    }
+}

GeeksForGeeks/March/18-3-24/README.md

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

LeetCode/March/18-3-24/README.md

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+Time complexity - O(n * logn)
+Space complexity - O(1)

LeetCode/March/18-3-24/Solution.java

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+class Solution 
+{
+    public int findMinArrowShots(int[][] points) 
+    {
+        if (points == null || points.length == 0)
+            return 0;
+
+        Arrays.sort(points, (a, b) -> Integer.compare(a[1], b[1]));
+
+        int arrows = 1;
+        int end = points[0][1];
+
+        for (int i = 1; i < points.length; i++) 
+        {
+            if (points[i][0] > end) 
+            {
+                arrows++;
+                end = points[i][1];
+            }
+        }
+
+        return arrows;
+    }
+}