Create subsequence.cpp

subsequence.cpp

@@ -0,0 +1,37 @@
+package RecursionAndBacktracking;
+
+import java.util.ArrayList;
+import java.util.Scanner;
+
+public class stringSubsequence {
+
+	public static void main(String[] args) {
+		// TODO Auto-generated method stub
+        Scanner sc = new Scanner(System.in);
+        String str = sc.next();
+        ArrayList<String> res = getSubSequence(str);
+        System.out.println(res);
+	}
+
+	private static ArrayList<String> getSubSequence(String str) {
+		// TODO Auto-generated method stub
+		if(str.length() == 0) {
+			ArrayList<String> bres = new ArrayList<>();
+			bres.add(" ");
+			return bres;
+		}
+
+		char ch = str.charAt(0);           // a
+		String ros = str.substring(1);     //bc
+		ArrayList<String> rres = getSubSequence(ros);   //[--,-c,b-,bc]
+		ArrayList<String> mres = new ArrayList<>();
+		for(String rstr: rres) {
+			mres.add(""+rstr);
+		}
+		for(String rstr : rres) {
+			mres.add(ch+rstr);
+		}
+		return mres;
+	}
+
+}