I changed my mind - Backtracking

darpanjbora · darpanjbora · commit b35aafffc7c0 · 2018-09-11T18:47:05.000+05:30
diff --git a/Backtracking/AllPermutationsOfAString.java b/Backtracking/AllPermutationsOfAString.java
@@ -0,0 +1,41 @@
+/**
+ * A string of length n has n! permutation.
+ */
+
+import java.util.*;
+import java.io.*;
+
+class AllPermutationsOfAString {
+
+    public static void main(String[] args){
+        Scanner sc = new Scanner(System.in);
+        String S = sc.nextLine();
+        int len = S.length();
+        AllPermutationsOfAString per = new AllPermutationsOfAString();
+        per.permute(S, 0, len-1);
+
+    }
+
+    public void permute(String S, int l, int r){
+        if (l == r)
+            System.out.println(S);
+        else{
+            for(int i=l; i<=r; i++){
+                S = swap(S, l, i);
+                permute(S, l+1, r);
+                S = swap(S, l, i);
+            }
+        }
+    }
+
+    //Swapping characters of a string.
+    public String swap(String a, int i, int j) 
+    { 
+        char temp; 
+        char[] charArray = a.toCharArray(); 
+        temp = charArray[i] ; 
+        charArray[i] = charArray[j]; 
+        charArray[j] = temp; 
+        return String.valueOf(charArray); 
+    } 
+}
