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..157ae2d71 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
@@ -1,12 +1,31 @@
 package com.codedifferently.lesson13;
 
+import java.util.HashMap;
+
 public class Lesson13 {
 
   /**
    * Provide the solution to LeetCode 3146 here:
    * https://leetcode.com/problems/permutation-difference-between-two-strings
    */
+
+  /**
+   * We need to return the absolute difference btw. a chars index in both 's' and 't' if s = "abc"
+   * and t = "bac" for s: a @index 0, b @index 1, c @index 2 for t: a @index 1, b @index 0, c @index
+   * 2 the math: |0 - 1| + |1 - 0| + \2 - 2| = |-1| + |1| + |0| = 1 + 1 + 0 = 2 we return 2
+   */
   public int findPermutationDifference(String s, String t) {
-    return 0;
+    var stringMap = new HashMap<Character, Integer>();
+    int total = 0;
+
+    for (int i = 0; i < s.length(); i++) {
+      stringMap.put(s.charAt(i), s.indexOf(s.charAt(i)));
+    }
+
+    for (int i = 0; i < t.length(); i++) {
+      int absDiff = Math.abs(stringMap.get(s.charAt(i)) - t.indexOf(s.charAt(i)));
+      total += absDiff;
+    }
+    return total;
   }
 }