diff --git a/contest/src/main/java/com/github/contest/hashTable/HashTableLeetcode.kt b/contest/src/main/java/com/github/contest/hashTable/HashTableLeetcode.kt
index 5d541ba0..557c034e 100644
--- a/contest/src/main/java/com/github/contest/hashTable/HashTableLeetcode.kt
+++ b/contest/src/main/java/com/github/contest/hashTable/HashTableLeetcode.kt
@@ -595,3 +595,21 @@ fun longestPalindrome(words: Array<String>): Int {
 
     return len
 }
+
+/**
+ * 594. Longest Harmonious Subsequence
+ */
+
+fun findLHS(nums: IntArray): Int {
+    val freq = nums.toList().groupingBy { it }.eachCount()
+    var longest = 0
+
+    for ((key, value) in freq) {
+        val more = key + 1
+        if (freq.contains(more)) {
+            longest = maxOf(longest, freq.getOrDefault(more, 0) + value)
+        }
+    }
+
+    return longest
+}
diff --git a/contest/src/main/java/com/github/contest/hashTable/HashTableProdVariant.kt b/contest/src/main/java/com/github/contest/hashTable/HashTableProdVariant.kt
index a80d0961..89e3e257 100644
--- a/contest/src/main/java/com/github/contest/hashTable/HashTableProdVariant.kt
+++ b/contest/src/main/java/com/github/contest/hashTable/HashTableProdVariant.kt
@@ -151,6 +151,19 @@ fun countVowelSubstringsProdVariantIII(word: String) = sequence {
     }
 }.sum()
 
+/**
+ * 594. Longest Harmonious Subsequence
+ * Prod Variant
+ */
 
+fun findLHSProdVariant(nums: IntArray): Int =
+    nums.toList().groupingBy { it }.eachCount().let { map ->
+        map.maxOf { (num, value) ->
+            val more = num + 1
+            if (map.contains(more)) {
+                map.getOrDefault(num, 0) + value
+            } else 0
+        }
+    }