Solved 3 of 4 questions posted on telegram channel.

telegramRecursionQuestions/ReverseAString.java

@@ -0,0 +1,35 @@
+package assignments.telegramRecursionQuestions;
+
+public class ReverseAString {
+
+	public static void main(String[] args) {
+		String s = "ApniKaksha";
+		reverse(s,0,s.length()-1);
+
+	}
+
+	public static void reverse(String s, int l , int r) {
+
+/*		Base Condition is basically when the length of the string is 
+ * 		1 - where we simply print the string.
+ * 		2 - where we exchange the characters and then print the string.
+ */
+		if(l>=r) {
+			System.out.println(s);
+			return;
+		}
+
+//		In the following code we are exchanging the characters of the string pairwise from the end.
+
+		char arr[] = s.toCharArray();
+		char temp = arr[l];
+		arr[l] = arr[r];
+		arr[r] = temp;
+		s = String.valueOf(arr);
+		reverse(s,l+1,r-1);
+
+
+
+	}
+
+}

telegramRecursionQuestions/StringPalindrome.java

@@ -0,0 +1,40 @@
+package assignments.telegramRecursionQuestions;
+
+public class StringPalindrome {
+
+	public static void main(String[] args) {
+		String s = "Naman";
+		if(isPalindrome(s,0,s.length()-1)) {
+			System.out.println("Yes");
+		}else {
+			System.out.println("No");
+		}
+
+	}
+
+	public static boolean isPalindrome(String g, int l, int r) {
+
+/* 		Base condition is when the length of the string is 
+ *  	1 - which implies that the string will be a palindrome.
+ *  	0 - which implies that there is no string so it can not be a palindrome.
+ */
+
+
+		String s = g.toLowerCase();
+		char[] arr = s.toCharArray();
+		if (arr.length==0) return false;
+		if (arr.length==1) return true;
+
+
+		if(arr[l]==arr[r] && l<=r) {
+			isPalindrome(s,l+1,r-1);
+			return true;
+
+
+		}
+
+
+		return false;
+	}
+
+}

telegramRecursionQuestions/SubSequencesOfString.java

@@ -0,0 +1,42 @@
+package assignments.telegramRecursionQuestions;
+import java.util.*;
+public class SubSequencesOfString {
+//Print all the subsequences of a string using recursion.
+	static Set<String> sett = new HashSet<>();
+	public static void main(String[] args) {
+
+
+
+		String s = "hello";
+
+
+		for(String a: getSubSequences(s,0)) {
+			System.out.println(a);
+		}
+
+
+	}
+
+	public static HashSet<String> getSubSequences(String s, int i){
+
+		if(i>=s.length()) {
+			return (HashSet<String>) sett;
+		}
+
+		int j = i+1;
+		while(j<=s.length()) {
+
+			sett.add(s.substring(i,j));
+
+			j++;
+
+		}
+		getSubSequences(s, i+1);
+		return (HashSet<String>) sett;
+
+	}}
+
+
+
+
+