Added codes for 2 April

GeeksForGeeks/April/02-4-24/GFG.java

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+//{ Driver Code Starts
+//Initial Template for Java
+
+import java.util.*;
+import java.lang.*;
+import java.math.*;
+import java.io.*;
+ 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;
+    }
+  public static void main(String[] args) throws IOException {
+    BufferedReader bu=new BufferedReader(new InputStreamReader(System.in));
+    int T=Integer.parseInt(bu.readLine());
+    while (T-- > 0) {
+
+      String s=bu.readLine();
+      Node root = buildTree(s);
+       if (root == null)
+        continue;
+      if (root.left == null && root.right == null)
+        continue;
+      Solution obj = new Solution();
+      int ans = obj.absolute_diff(root);
+      System.out.println(ans);
+    }
+  }
+}
+
+// } Driver Code Ends
+
+
+//User function Template for Java
+
+/*The Node structure is defined as
+struct Node {
+    int data;
+    Node *left;
+    Node *right;
+
+};
+*/
+class Solution
+{
+
+    int absolute_diff(Node root)
+    {
+        //Your code here
+        int ans = Integer.MAX_VALUE;
+        int prev = -1;
+        Deque<Node> stack = new ArrayDeque<>();
+
+        while (root != null || !stack.isEmpty()) 
+        {
+            while (root != null) 
+            {
+                stack.push(root);
+                root = root.left;
+            }
+
+            root = stack.pop();
+            if (prev >= 0)
+                ans = Math.min(ans, root.data - prev);
+
+            prev = root.data;
+            root = root.right;
+        }
+
+        return ans;
+    }
+}

GeeksForGeeks/April/02-4-24/README.md

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

LeetCode/April/02-4-24/README.md

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

LeetCode/April/02-4-24/Solution.java

@@ -0,0 +1,14 @@
+class Solution 
+{
+    public boolean isIsomorphic(String s, String t) 
+    {
+        Map<Character, Integer> charToIndex_s = new HashMap<>();
+        Map<Character, Integer> charToIndex_t = new HashMap<>();
+
+        for (Integer i = 0; i < s.length(); ++i)
+            if (charToIndex_s.put(s.charAt(i), i) != charToIndex_t.put(t.charAt(i), i))
+                return false;
+
+        return true;
+    }
+}