return string permu

Author: anmolpant

Diff for: Data Structures in Java/Level 1/Lecture 4 - Recursion 2/Assignments/Recursion2_ReturnPermutationsString.java

@@ -0,0 +1,34 @@
+
+public class Recursion2_ReturnPermutationsString {
+	public static String[] permutationOfString(String input){
+		// Write your code here
+        
+        //base case
+        if (input.length()==0){
+            String ans[] = {""};
+            return ans;
+        }
+        
+        //take first character and call recursion on the rest
+        String smallAns[] = permutationOfString(input.substring(1));
+        
+        //create new answer array with required number of positions
+        String ans[]  = new String[smallAns.length * input.length()];
+        
+        //add the first character at every position of the obtained permutations of the substring
+        int k = 0;
+        //loop over arrays
+        for(int i = 0; i<smallAns.length;i++){
+            //loop over strings
+            for(int j = 0; j<input.length(); j++){
+                //build each string as string = before + character + after
+                ans[k] = smallAns[i].substring(0,j) + input.charAt(0) + smallAns[i].substring(j,smallAns[i].length());
+                k++;
+            }
+        }
+        
+        return ans;
+		
+	}
+
+}