diff --git a/lesson_13/maps_java/maps_app/src/main/java/com/codedifferently/lesson13/Lesson13.java b/lesson_13/maps_java/maps_app/src/main/java/com/codedifferently/lesson13/Lesson13.java
index 0c981abbf..e3e6c4378 100644
--- a/lesson_13/maps_java/maps_app/src/main/java/com/codedifferently/lesson13/Lesson13.java
+++ b/lesson_13/maps_java/maps_app/src/main/java/com/codedifferently/lesson13/Lesson13.java
@@ -1,5 +1,5 @@
 package com.codedifferently.lesson13;
-
+import java.util.HashMap;
 public class Lesson13 {
 
   /**
@@ -7,6 +7,19 @@ public class Lesson13 {
    * https://leetcode.com/problems/permutation-difference-between-two-strings
    */
   public int findPermutationDifference(String s, String t) {
-    return 0;
+    int difference=0;
+    HashMap<Character, Integer> indexMap=new HashMap<>();
+
+        for (int i = 0; i < s.length(); i++) {
+            indexMap.put(s.charAt(i), i);
+        }
+        
+        for (int i = 0; i < t.length(); i++) {
+            char ch = t.charAt(i);
+            int indexInS = indexMap.get(ch);
+            difference += Math.abs(indexInS - i);
+        }
+        
+        return difference;
   }
 }
diff --git a/lesson_13/maps_ts/src/lesson13.ts b/lesson_13/maps_ts/src/lesson13.ts
index 5207487e2..ef4db1180 100644
--- a/lesson_13/maps_ts/src/lesson13.ts
+++ b/lesson_13/maps_ts/src/lesson13.ts
@@ -3,5 +3,18 @@
  * https://leetcode.com/problems/permutation-difference-between-two-strings
  */
 export function findPermutationDifference(s: string, t: string): number {
-  return 0;
+  let difference = 0;
+  const indexMap = new Map<string, number>();
+
+  for (let i = 0; i < s.length; i++) {
+    indexMap.set(s[i], i);
+  }
+
+  for (let i = 0; i < t.length; i++) {
+    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+    const indexInS = indexMap.get(t[i])!;
+    difference += Math.abs(indexInS - i);
+  }
+
+  return difference;
 }